Physical Processes

v = Δx/Δt v = velocity Δx = change in displacement Δt = change in time

What is the formula for finding the velocity of a moving object?

y=1/x or P=1/v

What is the function in an isothermal curve in a PV diagram?

Heat of fusion Heat of vaporization

What is the heat of transformation at a substance's melting point? What is the heat of transformation at a substance's boiling point?

V^2 = X^2 + Y^2 V^2 = 3^2 + 4^2 V^2 = 9 + 16 V^2 = 25 V = sqrt(25) V = 5 m/s

What is the magnitude of the vector with the following components? X = 3 m/s Y = 4 m/s

V^2 = X^2 + Y^2 V^2 = 5^2 + 9^2 V^2 = 25 + 81 V^2 = 106 V = sqrt(106) V = 10.3 m/s

What is the magnitude of the vector with the following components? X = 5 m/s Y = 9 m/s

V^2 = X^2 + Y^2 V^2 = 8^2 + 2^2 V^2 = 64 + 4 V^2 = 68 V = sqrt(68) V = 8.2 m/s

What is the magnitude of the vector with the following components? X = 8 m/s Y = 2 m/s

When internal energy increases, temperature increases. When internal energy decreases, temperature decreases.

What is the relationship between internal energy and temperature?

The entropy of a system and its surroundings will never decrease; it will always either remain zero or increase.

What is the relationship between the entropy of a system and its surroundings for any thermodynamic process?

It allows us to define a universal temperature scale.

What is the significance of the Zeroth Law of Thermodynamics?

1 cal/g*K 4.184 J/g*K

What is the specific heat for water? (both units of measurements)

1 cal/(g)(K) or 4.184 J/(g)(K)

What is the specific heat of water? (In both cal/g*K & J/g*K).

9.8 m/s^2

What is the value of acceleration due to gravity?

Adiabatic compression

What kind of thermodynamic process is being shown in the PV diagram?

Adiabatic expansion

What kind of thermodynamic process is being shown in the PV diagram?

Isobaric compression

What kind of thermodynamic process is being shown in the PV diagram?

Isobaric expansion

What kind of thermodynamic process is being shown in the PV diagram?

Isochoric cooling

What kind of thermodynamic process is being shown in the PV diagram?

Isochoric heating

What kind of thermodynamic process is being shown in the PV diagram?

Isothermal compression

What kind of thermodynamic process is being shown in the PV diagram?

Isothermal expansion

What kind of thermodynamic process is being shown in the PV diagram?

Kinetic energy of molecules (motion of molecules) Potential energy of molecules (intra and intermolecular forces) Thermal energy

What kinds of energies make up the internal energy of a system?

Answers: a, d and h apply. a. TRUE, since the line is in the positive region of the graph. b. FALSE, since there is an acceleration (i.e., a changing velocity). c. FALSE, since a negative velocity would be a line in the negative region (i.e., below the horizontal axis). d. TRUE, since the line is approaching the 0-velocity level (the x-axis). e. FALSE, since the line never crosses the axis. f. FALSE, since the line is not moving away from x-axis. g. FALSE, since the line has a negative or downward slope. h. TRUE, since the line is straight (i.e, has a constant slope).

1. Consider the graph at the right. The object whose motion is represented by this graph is ... (include all that are true): a. moving in the positive direction. b. moving with a constant velocity. c. moving with a negative velocity. d. slowing down. e. changing directions. f. speeding up. g. moving with a positive acceleration. h. moving with a constant acceleration.

Answer: B. 1. Find force of gravity Fg = m * a(g) Fg = 10 kg * 9.8 m/s^2 F(g) = 98 N 2. Find the value of the parallel component of Fg Angle between perpendicular component and Fg is equal to the angle of the incline, which is 30°. sinθ = opposite/hypotenuse sin(30) = Fg(parallel)/98 N sin(30) = 0.5 98 N * 0.5 = Fg(parallel) Fg(parallel) = 49 N We need 49 N in the opposite direction of Fg(parallel) to counter the force of the component.

A 10 kg wagon rests on a frictionless inclined plane. This plane makes an angle of 30° with the horizontal. Approximately how large is the force required to keep the wagon from sliding down the plane? A. 10 N B. 49 N C. 85 N D. 98 N

The point that connects the three strings is stationary, meaning that it will not accelerate. Therefore, the system is balanced, and there is no net force acting on the weight. The 100 N weight is exerting a gravitational force, meaning that the T1 string will be exerting a force of tension of 100 N downward from the stationary point. T1 = 100 N Since the downward force in this system is 100 N, that means the total upward force in the system is 100 N as well. Now we break both string vectors down into their vector components. However, we do not have to worry about that for T2. Since T2 is attached to the wall, it has no y-component, meaning that it will not exhibit any upward force in the system. This means that T3 will exhibit all of the upward force exhibited in the system, meaning that the magnitude of the y-component will equal 100 N. Using this, we can find the magnitude of T3. Remember that the angle between the string and the ceiling will also equal to the angle formed by the string and its x-component. sinθ = opposite/hypotenuse sin(30) = 100 N/T3 T3 = 100 N/sin(30) sin(30) = 1/2 or 0.5 T3 = 100 N/0.5 T3 = 200 N Since the stationary point is not exhibiting any net force, that means we know that the horizontal forces are balanced (equaling zero). To find the value of T2, we must determine the x-component of T3. cosθ = adjacent/hypotenuse cos(30) = T3x/200 N cos(30) = sqrt(3)/2 200 N * sqrt(3)/2 = T3x T3x = 100 sqrt(3) N T3x = T2 T2 = 100 sqrt(3) N Values of tension: T1 = 100 N T2 = 200 N T3 = 100 sqrt(3) N

A 100 N weight is attached to a string, and that string is attached to two other strings, where one string is attached to the wall, and the other is attached to the ceiling. The angle formed by the T3 string and the ceiling is 30°. What is the tension in the three strings?

Answer: A. F = ma m = 1000 kg F = 20 kN = 20000 N 20000 N = 1000 kg * a a = 20 m/s^2 a = v/t t = 8 s 20 m/s^2 = v/8 s v = 160 m/s

A 1000 kg rocket ship, travelling at 100 m/s, is acted upon by an average force of 20 kN applied in the direction of its motion for 8 s. What is the change in velocity of the rocket? A. 160 m/s B. 260 m/s C. 160,000 m/s D. 260,000 m/s

Answer: B. The force of friction on an object sliding down an incline equals the coefficient of friction times the normal force. The normal force is equal in magnitude to the perpendicular component of gravity, which is given by mg cosθ. As θ increases, cosθ decreases. Therefore, the normal force decreases as the angle of the incline increases.

A 20 kg wagon is released from rest from the top of a 15 m long lane, which is angled at 30° with the horizontal. Assuming that there is friction between the ramp and the wagon, how is this frictional force affected if the angle of the incline is increased? A. The frictional force increases B. The frictional force decreases C. The frictional force remains the same D. It cannot be determined from the information given

Answer: C. ΔL = αLΔT α = 1.1 x 10^-5 K^-1 L = 20 m ΔT = 110°C - 10°C = 100 K ΔL = 1.1 x 10^-5 K^-1 * 20 m * 100 K ΔL = 0.022 m = 2.2 cm 2.5 cm - 2.2 cm = 0.3 cm from the ground

A 20 m steel rod at 10°C is dangling from the edge of a building and is 2.5 cm from the ground. If the rod is heated to 110°C, will the rod touch the ground? (Note: α = 1.1 x 10^-5 K^-1) A. Yes, because it expands by 3.2 cm. B. Yes, because it expands by 2.6 cm. C. No, because it expands by 2.2 cm. D. No, because it expands by 1.8 cm.

Answer: B. Since we are looking for equilibrium: τ1 = τ2 τ1 = F1 * d1 * sinθ1 τ2 = F2 * d2 * sinθ2 F = m*a τ1 = (m1 * a1) * d1 * sinθ1 τ2 = (m2 * a2) * d2 * sinθ2 τ1 = (30 kg * 10 m/s^2) * 2 m * sin(90) τ2 = (90 kg * 10 m/s^2) * d2 * sin(90) τ1 = 600 N * m τ2 = 900 N * m * d2 600 N * m = 900 N * m * d2 d2 = 0.667 m d2 = 67 cm from the fulcrum

A 30 kg girl sits on a seesaw at a distance of 2 m from the fulcrum. Where must her father sit to balance the seesaw if he has a mass of 90 kg? A. 67 cm from the girl B. 67 cm from the fulcrum C. 133 cm from the girl D. 267 cm from the fulcrum

1. Find force of gravity Fg = m * a(g) Fg = 5 kg * 9.8 m/s^2 Fg = 49 N 2. Find normal force cosθ = adjacent/hypotenuse cos(30) = Fg(perpendicular)/49 N cos(30) = 0.866 49 N * 0.866 = Fg(perpendicular) Fg(perpendicular) = 42.4 N Fg(perpendicular) = F(N) F(N) = 42.4 N 3. Find acceleration of block sinθ = opposite/hypotenuse sin(30) = Fg(parallel)/49 N sin(30) = 0.5 49 N * 0.5 = Fg(parallel) Fg(parallel) = 24.5 N Fg(parallel) = m * a 24.5 N = 5 kg * a 24.5 N/5 kg = a a = 4.9 m/s^2 F(N) = 42.4 N a = 4.9 m/s^2

A 5 kg block slides down a frictionless incline at 30°. Find the normal force and acceleration of the block.

Vector

A _______________ is a measurement with a magnitude and a direction.

Jerk

A ________________ is considered to be a change in acceleration over time (m/s^3).

Scalar

A __________________ is a measurement with only a magnitude.

Fulcrum Fulcrum

A __________________ is a point of fixation (or pivot point) that an object is bound to that will cause it to rotate around if a force acts away from this pivot point. A _________________ does not have to be the actual center of mass of the object.

A. Vf = Vo + aΔt Vo = 10 m/s a = -9.8 m/s^2 Δt = 2 s Vf = 10 m/s + (-9.8 m/s^2) * 2 s Vf = -9.6 m/s Δy = 1/2 * a * t^2 + Vo * t Δy = 1/2 * (-9.8 m/s) * (2 s)^2 + 10 m/s * 2 s Δy = -19.6 + 20 Δy = 0.4 m (above the ledge) b) Since the object will be at its maximum height, its final velocity will equal 0 m/s. Vf^2 = Vo^2 + 2aΔy Vf = 0 m/s Vo = 10 m/s a = -9.8 m/s^2 (0 m/s)^2 = (10 m/s)^2 + 2 * (-9.8 m/s^2) * Δy 0 m^2/s^2 = 100 m^2/s^2 + (-19.6 m/s^2) * Δy -100 m^2/s^2 = -19.6 m/s^2 * Δy 100 m^2/s^2 = 19.6 m/s^2 * Δy Δy = 5.1 m Vf = Vo + aΔt 0 m/s = 10 m/s + (-9.8 m/s^2) * Δt -10 m/s = -9.8 m/s^2 * Δt 10 m/s = 9.8 m/s^2 * Δt Δt = 1.02 s

A ball is thrown vertically up into the air from a window ledge 30 meters above the ground with an initial velocity of 10 m/s. a) Find the velocity and position of the ball after two seconds. b) Find the distance and time at which the ball reaches its maximum height above the window ledge.

Answer: B. This is a projectile motion question. The horizontal component of the jumper's velocity will remain 3 m/s throughout the jump. The vertical component of his velocity starts at 0 m/s. After 0.5 seconds, it will be: Vy = Voy + at Vy = 0 m/s + (-9.8 m/s^2)(0.5 s) = -4.9 m/s To get the overall velocity, consider the horizontal and vertical velocities using vector analysis and find the resultant. Doing so gives: sqrt(3^2 + (4.9)^2) = 5.75 This magnitude (speed) is just a bit under 6, which matches most closely to (B).

A base jumper runs off a cliff with a speed of 3 m/s. Which of the following is closest to his speed after 0.5 seconds? A. 3 m/s B. 6 m/s C. 8 m/s D. 10 m/s

Q = mcΔT m = 3 kg = 3000 g c = 2.090 J/gK Tf = 0°C Ti = -40°C Q = 3000 g * 2.090 J/gK * (0°C - (-40)°C) Q = 250800 J Q(fus) = m * L(fus) m = 3000 g L(fus) = 333 J/g Q(fus) = 3000 g * 333 J/g Q(fus) = 999000 J Q = mcΔT m = 3000 g c = 4.184 J/gK Tf = 100°C Ti = 0°C Q = 3000 g * 4.184 J/gK * (100°C - 0°C) Q = 1255200 J Q(vap) = m * L(vap) m = 3000 g L(vap) = 2260 J/g Q(vap) = 3000 g * 2260 J/g Q(vap) = 6780000 J Q = mcΔT m = 3000 g c = 2.010 J/gK Tf = 160°C Ti = 100°C Q = 3000 g * 2.010 J/gK * (160°C - 100°C) Q = 361800 J 250800 999000 1255200 6780000 + 361800 9646800 J

A block of ice has a mass of 3 kg and is sitting at a temperature of -40°C. How much heat is needed to heat this block of ice to 160°C? (Specific heat of ice = 2.090 J/gK) (Specific heat of water = 4.184 J/gK) (Specific heat of steam = 2.010 J/gK) (Melting point of ice = 0°C) (Boiling point of water = 100°C) (L(fus) = 333 J/g) (L(vap) = 2260 J/g)

1. Find the force of gravity Fg = m * a(g) m = 10 kg a(g) = 9.8 m/s^2 Fg = 10 kg * 9.8 m/s^2 Fg = 98 N 2. Draw the components of the force of gravity 3. Find the angle formed between the Fg vector and its components Degree of incline equals angle between Fg and its perpendicular component, meaning that the angle between these two vectors would be 30°. Angle between Fg and its parallel component will equal to 90° - θ. Which is equal to 90° - 30° = 60°. 4. Use trigonometry to find the magnitude of the vector components cosθ = adjacent/hypotenuse cos(30) = Fg(perpendicular)/98 N cos(30) = sqrt(3)/2 98 N * sqrt(3)/2 = Fg(perpendicular) Fg(perpendicular) = 49 N * sqrt(3) sinθ = opposite/hypotenuse sin(30) = Fg(parallel)/98 N sin(30) = 1/2 98 N * 1/2 = Fg(parallel) Fg(parallel) = 49 N 5. Take in any opposing forces into consideration Since Fg(perpendicular) is perpendicular to the surface of the incline plane, it will be counteracted by the normal force. Fg(perpendicular) = F(N) F(N) = 49 * sqrt(3) N in opposite direction of perpendicular component. Since friction is negligible, there will be no forces opposing the parallel component of the force of gravity. Thus the block will be exhibiting a net force of 49 N in parallel to the surface of the incline plane. 6. Find acceleration using the net force F(net) = m * a F(net) = 49 N m = 10 kg 49 N = 10 kg * a 49 N/10 kg = a a = 4.9 m/s^2

A block of ice is on a ramp made of ice at an incline of 30°. The block of ice has a mass of 10 kg and friction is negligible. What would be the acceleration of the block as it slides down the ramp?

1. Find the force of gravity Fg = m * a(g) m = 10 kg a(g) = 9.8 m/s^2 Fg = 10 kg * 9.8 m/s^2 Fg = 98 N 2. Draw the components of the force of gravity 3. Find the angle formed between the Fg vector and its components Degree of incline equals angle between Fg and its perpendicular component, meaning that the angle between these two vectors would be 30°. Angle between Fg and its parallel component will equal to 90° - θ. Which is equal to 90° - 30° = 60°. 4. Use trigonometry to find the magnitude of the vector components cosθ = adjacent/hypotenuse cos(30) = Fg(perpendicular)/98 N cos(30) = sqrt(3)/2 98 N * sqrt(3)/2 = Fg(perpendicular) Fg(perpendicular) = 49 N * sqrt(3) sinθ = opposite/hypotenuse sin(30) = Fg(parallel)/98 N sin(30) = 1/2 98 N * 1/2 = Fg(parallel) Fg(parallel) = 49 N Fg(perpendicular) = 49 sqrt(3) N Fg(parallel) = 49 N

A block of ice is on a ramp made of ice at an incline of 30°. The block of ice has a mass of 10 kg and friction is negligible. What would be the magnitude of the perpendicular and parallel components of the force of gravity?

Velocity does not affect the force acting on the block since it is moving at a constant rate. For every action, there is an equal yet opposite reaction. F(g) = 5 kg * -9.8 m/s^2 F(g) = -49 N F(N) = 49 N F(N) cancels out F(g), meaning there is no net force acting on the block.

A block of ice with a mass of 5 kg is moving at a constant velocity of 5 m/s on a frictionless surface. What is the net force acting on the block?

For every action, there is an equal yet opposite reaction. F(g) = 5 kg * -9.8 m/s^2 F(g) = -49 N F(N) = 49 N F(N) cancels out F(g), meaning there is no net force acting on the block.

A block of ice with a mass of 5 kg is stationary on a frictionless surface. What is the net force acting on the block?

1. Determine the normal force acting on the block Fg = m * a(g) Fg = 5 kg * 9.8 m/s^2 Fg = 49 N Fg = F(N) F(N) = 49 N in opposite direction 2. Find the (maximum) force of static friction F(s) = μ(s) * F(N) μ(s) = 0.60 F(N) = 49 N F(s) = 0.60 * 49 N F(s) = 29.4 N 3.Find the net force acting on the stationary object F - F(s) = F(net) 100 N - 29.4 N = 70.6 N 4. Find the acceleration of the object from rest F(net) = m * a F(net) = 70.6 N m = 5 kg 70.6 N = 5 kg * a 70.6 N/5 kg = a a = 14.12 m/s^2 to the right

A block of wood has a mass of 5 kg and is sitting on the ground. The μ(s) between the block of wood and the ground is 0.60 while the μ(k) is 0.55. If the block was pushed with a force of 100 N to the right, find the acceleration of the block from its resting position.

1. Determine the normal force acting on the block Fg = m * a(g) Fg = 5 kg * 9.8 m/s^2 Fg = 49 N Fg = F(N) F(N) = 49 N in opposite direction 2. Find the force of kinetic friction F(k) = μ(k) * F(N) μ(k) = 0.55 F(N) = 49 N F(k) = 0.55 * 49 N F(k) = 26.95 N 3. Find the net force acting on the moving object F - F(k) = F(net) 100 N - 26.95 N = 73.05 N 4. Find the acceleration of the object while moving F(net) = m * a F(net) = 73.05 N m = 5 kg 73.05 N = 5 kg * a 73.05 N/5 kg = a a = 14.61 m/s^2 to the right

A block of wood has a mass of 5 kg and is sitting on the ground. The μ(s) between the block of wood and the ground is 0.60 while the μ(k) is 0.55. If the block was pushed with a force of 100 N to the right, find the acceleration of the block when it is moving.

1. Determine the normal force acting on the block Fg = m * a(g) Fg = 5 kg * 9.8 m/s^2 Fg = 49 N Fg = F(N) F(N) = 49 N in opposite direction 2. Find the (maximum) force of static friction F(s) = μ(s) * F(N) μ(s) = 0.60 F(N) = 49 N F(s) = 0.60 * 49 N F(s) = 29.4 N 3. Find the force of kinetic friction F(k) = μ(k) * F(N) μ(k) = 0.55 F(N) = 49 N F(k) = 0.55 * 49 N F(k) = 26.95 N 4. Find the difference between the two forces F(s) - F(k) = F 29.4 N - 26.95 N = F F = 2.45 N

A block of wood has a mass of 5 kg and is sitting on the ground. The μ(s) between the block of wood and the ground is 0.60 while the μ(k) is 0.55. If the block was pushed with a force of 100 N to the right, find the difference between the force of static friction and the force of kinetic friction.

1. Find the force of gravity Fg = m * a(g) m = 10 kg a(g) = 9.8 m/s^2 Fg = 10 kg * 9.8 m/s^2 Fg = 98 N 2. Draw the components of the force of gravity 3. Find the angle formed between the Fg vector and its components Degree of incline equals angle between Fg and its perpendicular component, meaning that the angle between these two vectors would be 30°. Angle between Fg and its parallel component will equal to 90° - θ. Which is equal to 90° - 30° = 60°. 4. Use trigonometry to find the magnitude of the vector components cosθ = adjacent/hypotenuse cos(30) = Fg(perpendicular)/98 N cos(30) = sqrt(3)/2 98 N * sqrt(3)/2 = Fg(perpendicular) Fg(perpendicular) = 49 N * sqrt(3) sinθ = opposite/hypotenuse sin(30) = Fg(parallel)/98 N sin(30) = 1/2 98 N * 1/2 = Fg(parallel) Fg(parallel) = 49 N 5. Take in any opposing forces into consideration Since Fg(perpendicular) is perpendicular to the surface of the incline plane, it will be counteracted by the normal force. Fg(perpendicular) = F(N) F(N) = 49 * sqrt(3) N in opposite direction of perpendicular component. Since friction is not considered negligible, then there will be a force of fricition. Since the block is stationary, then that means that the force of static friction must be at least equal to the parallel component of the force of gravity. Fg(parallel) = F(s) F(s) = 49 N

A block of wood is on a ramp made of wood at an incline of 30°. The block of ice has a mass of 10 kg and the block is stationary. What would be the force of friction acting on the block?

Scalar Speed

A brick is being pushed 2.5 m/s. Is this an example of a vector or a scalar? What type of vector/scalar is this example?

Vector Velocity

A brick is pushed 2.5 m/s to the right. Is this an example of a vector or a scalar? What type of vector/scalar is this example?

Vector Displacement

A brick was moved 5 meters to the right. Is this an example of a vector or a scalar? What type of vector/scalar is this example?

Answer: C. First convert seconds to hours: 6 s * 1 min * 1 hr = 6 hours = 1/600 hours 60 s 60 min 3600 Find acceleration: a = Δv/Δt Δv = -40 km/hr Δt = 1/600 hr a = -40 km/hr/(1/600 hr) = -24000 a = |-24000| = 24000 a = 24000 km/hr^2

A car is traveling at 40 km/hr and the driver puts on the brakes, bringing the car to rest in a time of 6 s. What is the magnitude of the average acceleration of the car? A. 200 km/hr^2 B. 12000 km/hr^2 C. 24000 km/hr^2 D. 30000 km/hr^2

Answer: A. To find the amount of heat needed to bring the substance to its melting point, you can use the specific heat. To heat one mole of the substance one unit Kelvin, it would take 1 J of heat. After the substance reaches its melting point, additional heat is needed to actually induce the phase change. Therefore, the total amount of heat required is greater than 1 J.

A certain substance has a specific heat of 1 J/mol*K and a melting point of 350 K. If one mole of the substance is currently at a temperature of 349 K, how much energy must be added in order to melt it? A. More than 1 J B. Exactly 1 J C. Less than 1 J but more than 0 J D. Less than 0 J

Answer: A. The firefighter's acceleration is always directed downward, whereas his velocity starts out horizontal and gradually rotates downward as his downward velocity increases. Therefore, as time progresses, the angle between his velocity and acceleration decreases, which means that the maximum angle occurs at the instant he jumps.

A firefighter jumps horizontally from a burning building with an initial speed of 1.5 m/s. At what time is the angle between his velocity and acceleration vectors the greatest? A. The instant he jumps B. When he reaches terminal velocity C. Halfway through his fall D. Right before he lands on the ground

W = P*ΔV P = 3.6 x 10^5 Pa ΔV = 1.5 m^3 - 1.0 m^3 = 0.5 m^3 W = 3.6 x 10^5 Pa * 0.5 m^3 = 180000 J = 180 kJ Work is being done by the gas: -180 kJ W = -180 kJ ΔU = Q + W ΔU = 300 kJ - 180 kJ = 120 kJ ΔU = 120 kJ

A gas in a cylinder is kept at a constant pressure of 3.6 x 10^5 Pa while 300 kJ of heat is added to it, causing the gas to expand from 1.0 m^3 to 1.5 m^3. Find the work done by the gas and the change in internal energy of the gas.

Answer: B. Using the Pythagorean theorem, calculate the magnitude of the man's displacement: x = sqrt(30^2 + 40^2) = 50 m His total distance traveled is equal to 30 + 40 = 70 m. Therefore, the difference between these two is 20 m.

A man walks 30 m east and then 40 m north. What is the difference between his traveled distance and his displacement? A. 0 m B. 20 m C. 50 m D. 70 m

ΔL = αLΔT α = 10^-6 K^-1 L = 2 m ΔT = 80 °C - 1080 °C = -1000 K ΔL = 10^-6 K^-1 * 2 m * -1000 K ΔL = -0.002 m ΔL = Lf - Li -0.002 m = Lf - 2 m Lf = 2 m - 0.002 m Lf = 1.998 m

A metal rod of length 2 m has a coefficient of linear expansion of 10^-6 K^-1. It is cooled from 1080 °C to 80 °C. What is the final length of the rod?

Scalar Distance

A person moved a brick by 5 meters? Is this an example of a vector or a scalar? What type of vector/scalar is this example?

Since elevator is stationary a(net) = 0 m/s^2 F(g) = m*a(g) m = 10 kg a(g) = -9.8 m/s^2 F(g) = 10 kg * -9.8 m/s^2 F(g) = -98 N F(N) = -F(g) F(N) = 98 N

A person with a mass of 10 kg is standing in a stationary elevator. What would be the total normal force acting on the person.

a(net) = 2 m/s^2 a(g) = -9.8 m/s^2 m = 10 kg F(N) = m * ((-a(g)) + a(net)) F(N) = 10 kg * (9.8 m/s^2 + 2 m/s^2) F(N) = 118 N or... F(N) = -F(g) + F(net) F(g) = 10 kg * -9.8 m/s^2 = -98 N F(net) = 10 kg * 2 m/s^2 = 20 N F(N) = 98 N + 20 N F(N) = 118 N

A person with a mass of 10 kg stands in an elevator that accelerates upward at 2 m/s^2. What is the normal force acting on the person?

a(net) = -2 m/s^2 a(g) = -9.8 m/s^2 m = 10 kg F(N) = m * ((-a(g)) + a(net)) F(N) = 10 kg * (9.8 m/s^2 - 2 m/s^2) F(N) = 78 N or... F(N) = -F(g) + F(net) F(g) = 10 kg * -9.8 m/s^2 = -98 N F(net) = 10 kg * -2 m/s^2 = -20 N F(N) = 98 N - 20 N F(N) = 78 N

A person with a mass of 10 kg stands in an elevator that is decelerating at 2 m/s^2 for 1 second. What is the normal force acting on the person?

Since velocity is constant, no net forces are acting on the person, thus a(net) is zero. F(N) = m * (-a(g)) m = 10 kg a(g) = -9.8 m/s^2 F(N) = 10 kg * 9.8 m/s^2 F(N) = 98 N

A person with a mass of 10 kg stands in an elevator that is moving at a constant velocity of 2 m/s. What is the normal force acting on the person?

τ1 + τ2 = 0 τ1 = 5 N * 10 m τ2 = -F * 5 m 5 N * 10 m + (-F) * 5 m = 0 50 N * m - 5 m * F = 0 50 N * m = 5 m * F F = 10 N

A plank of wood is nailed to the wall at a certain point. You apply two different forces at two different points away from the nail. However, the plank does not rotate at all from these forces. One of the forces is 10 m to the right of the nail and is exerting a force of 5 N in the clockwise direction. The other force is 5 m to the left of the nail and is exerting a force in the counterclockwise direction. What is the force of the torque to the left of the nail?

a) First, find initial vertical velocity: Voy = Vo * sinθ Voy = 50 m/s * 0.6 Voy = 30 m/s Now solve for time: Since it was fired from the ground level, Δy = 0 Δy = 1/2 * ay * t^2 + Voy * t 0 m = 1/2 * -10 m/s^2 * t^2 + 30 m/s * t 0 m = - 5 m/s^2 * t^2 + 30 m/s * t 5 m/s^2 * t^2 = 30 m/s * t t^2 = 6 m/s * t 0^2 = 6 * 0 or 6^2 = 6 * 6 t = 0 s at initial position t = 6 s at final position b) First find initial horizontal velocity: Vox = Vo * cosθ Vox = 50 m/s * 0.8 Vox = 40 m/s Now solve for horizontal distance: Δx = 1/2 * ax * t^2 + Vox * t Δx = 1/2 * (0 m/s^2) * (6 s)^2 + 40 m/s * 6 s Δx = 0 m + 240 m Δx = 240 m

A projectile is fired from the ground level with an initial velocity of 50 m/s and an initial angle of elevation of 37°, as shown below. Assuming g = 10 m/s^2, find the following: (Note: sin(37°) = 0.6; cos(37°) = 0.8) a) The projectile's total time in flight b) The total horizontal distance traveled

Answer: C. We only need to analyze the motion in the vertical dimensions to answer this question. If both the rock and ball began with no vertical velocity, they would reach the ground at the same time. However, because the rock begins with an upward component of velocity, it will take time to reach a maximum height before falling back toward the ground. Functionally, the rock's free fall thus starts higher and later than the ball's. The rock will necessarily hit the ground after the ball.

A rock (m = 2 kg) is shot up vertically at the same time that a ball (m = 0.5 kg) is projected horizontally. If both start from the same height: A. the rock and ball will reach the ground at the same time. B. the rock will reach the ground first. C. the ball will reach the ground first. D. the rock and ball will collide in the air before reaching the ground.

Yes there is a net force acting on the rock. 5 N from gravity 1 N from air resistance 1 N - 5 N = -4 N or 4 N downward. -4 N or 4 N downward

A rock is falling from the sky with a force of 5 N, but meets a bit of air resistance of 1 N. Is there a net force acting on that rock? If so, what is the net force acting on the rock.

No, there is no net force acting on the rock. According to Newton's 3rd Law, as the rock is exerting a weight of 5 N onto the ground, the ground is exerting a normal force of 5 N onto the rock.

A rock is resting on the ground and is exerting a force of 5 N on the ground; the ground is also exerting a normal force of 5 N on the rock. Is there a net force acting on the rock? If so, what is the net force acting on the rock?

No, there is no net force acting on the rock. Since all the forces canceled each other out (gravity and normal force cancel out, and push and friction cancels each other out), there is no net force.

A rock is resting on the ground and is exerting a force of 5 N on the ground; the ground is also exerting a normal force of 5 N on the rock. A man is pushing the rock with a force of 2 N to the right, with a friction force of 2 N that opposed it. Is there a net force acting on that rock? If so, what is the net force acting on the rock.

Yes, there is a net force acting on the rock. The normal force and force of gravity cancels each other out, but the force the man is pushing with against the rock is greater than the force of friction. 3 N - 2 N = 1 N 1 N to the right

A rock is resting on the ground and is exerting a force of 5 N on the ground; the ground is also exerting a normal force of 5 N on the rock. A man is pushing the rock with a force of 3 N to the right, with a friction force of 2 N that opposed it. Is there a net force acting on that rock? If so, what is the net force acting on the rock.

Yes, there is a net force acting on the rock. Normal force and force of gravity cancel each other out. 4 N from the man pushing right 2 N from friction 1 N from the man pushing left 4 N - 2 N - 1 N = 1 N to the right 1 N to the right

A rock is resting on the ground and is exerting a force of 5 N on the ground; the ground is also exerting a normal force of 5 N on the rock. A man is pushing the rock with a force of 4 N to the right, with a friction force of 2 N that opposed it. Another man is pushing the rock in the opposite direction of the first man with a force of 1 N. Is there a net force acting on that rock? If so, what is the net force acting on the rock.

1. Since the seesaw is in equilibrium, τ1 = τ2 τ = F * d * sinθ F = m * a F1 * d1 * sinθ1 = F2 * d2 * sinθ2 θ1 = 90° θ2 = 90° F1 = 10 kg * 10 m/s^2 = 100 N F2 = ? d1 = 2 m d2 = 0.5 m 100 N * 2 m * sin(90°) = F2 * 0.5 m * sin(90°) 200 N * m * 1 = F2 * 0.5 m * 1 200 N * m = F2 * 0.5 m 400 N = F2 F = m * a 400 N = m * 10 m/s^2 m = 40 kg

A seesaw with a mass of 5 kg has one block of mass 10 kg two meters to the left of the fulcrum and another block 0.5 m to the right of the fulcrum. If the seesaw is in equilibrium, find the mass of block 2.

Answer: A. Calorimeters are our best approximations of isolated systems, where neither energy nor matter is exchanged with the environment. By failing to use an insulating layer and failing to fully contain the system, heat can be exchanged with the environment and matter may be dispersed, creating an open system.

A student making a coffee cup calorimeter fails to use a second coffee cup and inadequately seals the lid. What was her initial goal, and what was the result of this mistake? A. She was trying to create an isolated system but created an open system instead. B. She was trying to create an isolated system but created a closed system instead. C. She was trying to create a closed system but created an open system instead. D. She was trying to create a closed system but created an isolated system instead.

The weight attached to the string is not accelerating, which means that there is no net forces acting on the weight. This means that the force of tension is counteracting the force of gravity being exerted on the weight. Since the weight is exerting a force of 100 N downward, it means that the string is exhibiting a force of tension of 100 N upward.

A weight of 100 N is suspended in the air by a string attached to the ceiling. What would be the force of tension of the string?

a) First convert 280 km/h to m/s 280 km/h * 1000 m * 1 h * 1 min = 77.78 m/s 1 km 60 min 60 s a = Δv/Δt a = 1 m/s^2 Δv = 77.78 m/s 1 m/s^2 = 77.78 m/s/Δt Δt = 77.78 m/s/1 m/s^2 Δt = 77.78 s b) x = Va * Δt Va = (77.78 m/s + 0 m/s)/2 = 38.89 m/s x = 38.89 m/s * 77.78 s = 3024.86 m

An Airbus A380 plane has a takeoff velocity of 280 km/h in the direction of the runway and has a constant acceleration of 1 m/s^2. a) How long will it take for the plane to take off? b) How long does the runway need to be in order for the plane to take off?

Answer: A. The forces on the elevator are the tension upward and the weight downward, so the net force on the elevator is the difference between the two. For the elevator to accelerate upwards, the tension in the cable will have to be greater than the maximum weight so that there is a net force directed upwards.

An elevator is designed to carry a maximum weight of 9800 N (including its own weight), and to move upward at a speed of 5 m/s after an initial period of acceleration. What is the relationship between the maximum tension in the elevator cable and the maximum weight of the elevator while the elevator is accelerating upward. A. The tension is greater than 9800 N B. The tension is less than 9800 N C. The tension equals 9800 N D. It cannot be determined from the information given

Zero

An object that is moving at a constant velocity has ______________________ acceleration.

repulsion electrons

At a microscopic level, what's causing the normal force to act on the block is the ___________________ between ___________________ in the object and the surface.

Answer: A. Vf = Vo + aΔt a = -9.8 m/s^2 Δt = 2 s First object: Vo = -5 m/s Since object is being thrown in the same direction as gravity, so velocity is negative Vf = -5 m/s + (-9.8 m/s^2) * 2 s Vf = -24.6 m/s |-24.6 m/s| - |-5 m/s| = 19.6 m/s Second object: Vo = +10 m/s Since object is being thrown in the opposite direction of gravity, so velocity is positive. Vf = 10 m/s + (-9.8 m/s^2) * 2 Vf = -9.6 m/s |-9.6 m/s| - | -10 m/s| = 0.4 m/s 19.6 m/s > 0.4 m/s The first object has a greater change in speed

At a place where g = 9.8 m/s^2, an object is thrown vertically downward with a speed of 5 m/s while a different object is thrown vertically upward with a speed of 10 m/s. Which object undergoes a greater change in speed in a time of 2 s. A. The first object has a greater change in speed B. The second object has a greater change in speed C. Both objects undergo the same change ins speed D. It cannot be determined from the information given

The product of sine and cosine is maximized when the angle is 45°. Because horizontal displacement relies on both measurements, the maximum horizontal displacement will also be achieved at this angle. Vertical displacement will always be zero as the object returns to the starting point. Objects launched vertically will experience the greatest vertical distance.

At what angle of launch is a projectile going to have the greatest horizontal displacement? What angle will result in the greatest vertical displacement, assuming a level surface?

Constant velocity

Being at rest feels similar as being at __________________________________.

v = x/t v = 3 m/s x = 720 m 3 m/s = 720 m/t t = 720 m/3 m/s = 240 seconds t = 240 seconds

Ben is running at a constant velocity of 3 m/s to the east. How long will it take to travel 720 meters?

Yes. A object that has no forces acting on it will either be at rest, or moving at a constant velocity.

Can a moving object be in equilibrium? Why or why not?

Answer: C. Because the question stem indicates that centrifugal force is reactionary and gives its direction, we can draw the conclusion that it is a reaction to the centripetal force. According to Newton's third law, these forces must have equal magnitude and opposite direction (antiparallel).

Centrifugal force is an apparent outward force during circular motion. It has been described as a reaction force according to Newton's third law. Which of the following statements is most likely to be correct regarding centrifugal force? A. Centrifugal force exists only for uniform circular motion, not nonuniform circular motion B. Centrifugal force exists only when tension or a normal force provides centripetal acceleration C. Centrifugal force always acts antiparallel to the centripetal force vector D. Centrifugal force is result of repulsive electrostatic interactions C. D.

Radially

Centripetal force is pointed ____________________ in regards to the center of a circular path.

Kinetic energy (movement of particles) Potential energy (intramolecular and intermolecular forces)

Changes in temperature relates to changes in ______________ energy, while phase changes relates to changes in __________________ energy.

Since the planet has no rotation, and the block has no relative motion towards the planet, and it is not accelerating in any direction, the net forces acting on the block must equal zero. Therefore, the gravitational force and the normal force must equal each other if the net force is zero.

Consider the following scenario: A planet known as Lubricon VI is a planet that is made of a yet-to-be-discovered element called Lubrica, which is said to be frictionless. The planet is perfectly spherical, it has no rotation, and it has no atmosphere (it is surrounded by a complete vacuum). If a block of ice is stationary on the planet, will the normal force and gravitational force equal to each other.

There is no net forces acting on the block, meaning there is no acceleration acting on the block. Therefore, the block will continue moving along the "equator" forever in the direction of the velocity.

Consider the following scenario: A planet known as Lubricon VI is a planet that is made of a yet-to-be-discovered element called Lubrica, which is said to be frictionless. The planet is perfectly spherical, it has no rotation, and it has no atmosphere (it is surrounded by a complete vacuum). If a block of ice is travelling around the planet's "equator" at a constant velocity of 1 km/hr, will the block stop moving at a certain period of time?

If there were no net forces acting on the block, the block would not stay on the planet's surface. In order for the block to stay on the planet's surface, there needs to be a little bit of centripetal force acting on the block as it rotates around the planet. Thus, the centripetal acceleration will cause the force of gravity to be greater than the normal force acting on the block.

Consider the following scenario: A planet known as Lubricon VI is a planet that is made of a yet-to-be-discovered element called Lubrica, which is said to be frictionless. The planet is perfectly spherical, it has no rotation, and it has no atmosphere (it is surrounded by a complete vacuum). If a block of ice moves along the planet's surface at a constant velocity of 1 km/hr, is the normal force equal to the gravitational force?

The change of total internal energy of a system is equal to the amount of heat transferred to the system plus the amount of work exerted on the system. Energy can neither be created nor destroyed, it can just be converted from one form to another.

Define the First Law of Thermodynamics.

Macroscopic An increase in disorder. Statistical The measure of the spontaneous dispersal of energy at a specific temperature, increasing the number of available microstates for a given molecule.

Describe entropy on a macroscopic level and in statistical terms.

Linear thermal expansion is only applicable to solids. Rising temperatures lead to an increase in length Falling temperatures lead to a decrease in length The change in length is proportional to the original length and the change in temperature.

Describe how linear thermal expansion can change the physical properties of matter based on temperature.

Volumetric thermal expansion is applicable to both solids and liquids. Rising temperatures lead to an increase in volume. Falling temperatures lead to a decrease in volume. The change in volume is proportional to the original volume and the change in temperature.

Describe how volumetric thermal expansion can change the physical properties of matter based on temperature.

When two objects come into thermal contact with one another, thermal energy will spontaneously flow from the hotter object to the cooler object, until thermal equilibrium is achieved. In a closed system, energy will spontaneously and irreversibly go from being localized to being spread out (dispersed). The total change in entropy of a system plus its surroundings will always increase for a spontaneous process.

Describe the Second Law of Thermodynamics.

The entropy of a perfect crystal (atoms are perfectly aligned) of any pure substance approaches zero as the temperature approaches absolute zero.

Describe the Third Law of Thermodynamics.

If object A is in thermal equilibrium with object B, and object B is in thermal equilibrium with object C, then object A is in thermal equilibrium with object C.

Describe the Zeroth Law of Thermodynamics

Objects that we see moving at a constant velocity in our everyday life are actually being interfered with various forces in our everyday life, such as friction, air resistance, and gravity.

Despite what Newton's first law says, we do not see objects that are moving at a constant velocity keep moving, we instead see these objects slow down. Why is that?

x = 1/2 * a * t^2 + Vo * t x = 1/2 * 12.5 m/s^2 * (4 s)^2 + 0 * 4 s x = 1/2 * 12.5 m/s^2 * 16 s^2 x = 100 m

Determine how far a car has traveled after 4 seconds of acceleration at 12.5 m/s^2 at constant velocity.

Initial position Final position

Displacement connects in a straight line the objects ___________________________ and _________________________.

the actual pathway traveled net change in position

Displacement does not account for ________________________________, it only accounts for ________________________________.

Yes, it does. Gravity exists between any two objects. However, gravity is typically only significant on a planetary level, since smaller scale gravity between objects is so small compared to other forces acting, that it is considered to be negligible.

Does gravity exist between your notebook and your hand? Explain your reasoning.

No, an isobaric process will still be represented by the equation: ΔU = Q + W

Does the equation for the first law of thermodynamics change if the process is isobaric? If yes, what changes?

Yes, the equation does change if the process is isochoric. An isochoric process is defined as a process in which the volume of the system does not change. This would mean that: ΔV = 0 If ΔV is zero, then regardless of what the value of the pressure is, the value of the work will equal zero. W = 0 Since work will equal zero in an isochoric process, the value of the change in internal energy will equal the value of heat added/removed to/from the system. ΔU = Q

Does the equation for the first law of thermodynamics change if the process is isochoric? If yes, what changes?

Yes, the equation does change if the process is isothermal. An isothermal process is defined as a process in which the temperature in the system does not change. Which means: ΔT = 0 Since temperature is proportional to internal energy then that means that the change in internal energy will not change either. In other words: ΔU = 0 This means that heat and work must be equal in magnitude but in opposite directions (one value is positive while the other value is negative). So this would mean that: I Q I = I W I

Does the equation for the first law of thermodynamics change if the process is isothermal? If yes, what changes?

Yes, the equation does change if the process is adiabatic. An adiabatic process is defined as a process in which there is no net flow of heat between the system and the surroundings. Therefore: Q = 0 Since the value of heat is equal to zero, the change in internal energy of the system will be determined by the work done on/by the system. ΔU = W

Does the equation for the first law of thermodynamics change if the process was adiabatic? If yes, what changes?

No, temperature is constant when an object undergoes a phase change.

Does the temperature of an object change when it undergoes a phase change?

Water has greater potential energy than ice due to the alterations in the intramolecular and intermolecular forces of the particles, leading to more microstates. Water and ice have the same average kinetic energy since both are sitting at 0°C.

Does water have greater potential energy than ice at freezing temperature? What about kinetic energy?

1st: Prior to the collision, the vehicle is traveling at a constant velocity, which indicates that there is no acceleration and no unbalanced net force. 2nd: The collision with the wall creates a sudden deceleration. Because there is acceleration, there must be a net force. The value of the net force can be calculated by multiplying the mass of the car times the acceleration. 3rd: When the car collides with the wall, the car exerts a force on the wall. Simultaneously, the wall exerts a force of equal magnitude in the opposite direction on the car.

During a crash test, a 500 kg car is driven at a constant velocity of 50 mph until it hits a wall without braking. Apply all three of Newton's laws to this situation.

F(g) = (G * m1 * m2)/(r^2) G = 6.67 x 10^-11 N * m^2/kg^2 m1 = 1.67 x 10^-27 kg m2 = 9.11 x 10^-31 kg r = 10^-11 m F(g) = (6.67 x 10^-11 N * m^2/kg^2) * (1.67 x 10^-27 kg) * (9.11 x 10^-31 kg) (10^-11 m)^2 Fg = 1.02 x 10^-45 N

Find the gravitational force between an electron and a proton that are 10^-11 m apart. (Note: mass of a proton = 1.67 x 10^-27 kg; mass of an electron = 9.11 x 10^-31 kg).

sinθ = opposite/hypotenuse sin(30°) = Vy/10 m/s 10 * sin(30°) = 5 m/s cosθ = adjacent/hypotenuse cos(30°) = Vx/10 m/s 10 * cos(30°) = 5 sqrt(3) or 8.66 m/s Vx = 5 sqrt(3) or 8.66 m/s Vy = 5 m/s

Find the x- and y- components of the following vector: V = 10 m/s θ = 30°

sinθ = opposite/hypotenuse sin(50°) = Vy/13 m 13 * sin(50°) = 10 m cosθ = adjacent/hypotenuse cos(50°) = Vx/13 m 13 * cos(50°) = 8.36 m Vx = 8.36 m Vy = 10 m

Find the x- and y- components of the following vector: V = 13 m θ = 50°

sinθ = opposite/hypotenuse sin(60°) = Vy/15 m/s 15 * sin(60°) = 7.5 sqrt(3) or 13 m/s cosθ = adjacent/hypotenuse cos(60°) = Vx/15 m/s 15 * cos(60°) = 7.5 m/s Vx = 7.5 m/s Vy = 7.5 sqrt(3) or 13 m/s

Find the x- and y- components of the following vector: V = 15 m/s θ = 60°

sinθ = opposite/hypotenuse sin(45°) = Vy/7 m 7 * sin(45°) = 7/sqrt(2) or 4.95 m cosθ = adjacent/hypotenuse cos(45°) = Vx/7 m 7 * cos(45°) = 7/sqrt(2) or 4.95 m Vx = 7/sqrt(2) or 4.95 m Vy = 7/sqrt(2) or 4.95 m

Find the x- and y- components of the following vector: V = 7 m θ = 45°

Δx = Va * Δt Δx = difference in displacement Va = average velocity = (Vf + Vo)/2 Δt = difference in time

For one-dimensional motions, what is the kinematic formula to use when acceleration is not given?

Vf = Vo + aΔt Vf = Final velocity Vo = Initial velocity a = acceleration Δt = difference in time

For one-dimensional motions, what is the kinematic formula to use when displacement is not given?

Δx = 1/2 * a * Δt^2 + Vo * Δt Δx = difference in displacement Δt = difference in time a = acceleration Vo = initial velocity

For one-dimensional motions, what is the kinematic formula to use when final velocity is not given?

Vf^2 = Vo^2 + 2aΔx Vf = final velocity Vo = initial velocity a = acceleration Δx = difference in displacement

For one-dimensional motions, what is the kinematic formula to use when time is not given?

Velocity = Constant positive Acceleration is zero

For the graph, answer the following: Is the velocity positive, negative, or constant? Is the acceleration increasing, decreasing, or zero?

Velocity = negative Acceleration is decreasing

For the graph, answer the following: Is the velocity positive, negative, or constant? Is the acceleration increasing, decreasing, or zero?

Velocity = negative Acceleration is increasing

For the graph, answer the following: Is the velocity positive, negative, or constant? Is the acceleration increasing, decreasing, or zero?

Velocity = positive Acceleration is decreasing

For the graph, answer the following: Is the velocity positive, negative, or constant? Is the acceleration increasing, decreasing, or zero?

Velocity = positive Acceleration is increasing

For the graph, answer the following: Is the velocity positive, negative, or constant? Is the acceleration increasing, decreasing, or zero?

Δx = Vax * Δt Δt = difference in time Δx = difference in horizontal displacement Vax = Average horizontal velocity

For two-dimensional horizontal projectile motions, what is the kinematic formula to use when acceleration is not given?

Vfx = Vox + axΔt Vfx = final horizontal velocity Vox = initial horizontal velocity ax = horizontal acceleration (usually 0 m/s^2) Δt = difference in time

For two-dimensional horizontal projectile motions, what is the kinematic formula to use when displacement is not given?

Δx = 1/2 * ax * Δt^2 + Vox * Δt Δt = difference in time Δx = difference in horizontal displacement ax = horizontal acceleration (usually 0 m/s^2) Vox = initial horizontal velocity

For two-dimensional horizontal projectile motions, what is the kinematic formula to use when final velocity is not given?

Vfx^2 = Vox^2 + 2ax * Δx Vfx = final horizontal velocity Vox = initial horizontal velocity ax = horizontal acceleration (usually 0 m/s^2) Δx = difference in horizontal displacement

For two-dimensional horizontal projectile motions, what is the kinematic formula to use when time is not given?

Δy = Vay * Δt Δt = difference in time Δy = difference in vertical displacement Vay = Average vertical velocity

For two-dimensional vertical projectile motions, what is the kinematic formula to use when acceleration is not given?

Vfy = Voy + ayΔt Vfy = final vertical velocity Voy = initial vertical velocity ay = vertical acceleration (usually -9.8 m/s^2) Δt = difference in time

For two-dimensional vertical projectile motions, what is the kinematic formula to use when displacement is not given?

Δy = 1/2 * ay * Δt^2 + Voy * Δt Δt = difference in time Δy = difference in vertical displacement ay = vertical acceleration (usually -9.8 m/s^2) Voy = initial vertical velocity

For two-dimensional vertical projectile motions, what is the kinematic formula to use when final velocity is not given?

Vfy^2 = Voy^2 + 2ay * Δy Vfy = final vertical velocity Voy = initial vertical velocity ay = vertical acceleration (usually -9.8 m/s^2) Δy = difference in vertical displacement

For two-dimensional vertical projectile motions, what is the kinematic formula to use when time is not given?

Answer: C. The total work done by the cycle is the sum of the work of paths A, B, and C, or the area within the cycle. Because the area bounded by A, B, and C is a triangle, with a base of 5 m^3 and a height of 3 Pa, we can calculate the area as 1/2(5 m^3)(3 Pa) = 7.5 J. Clockwise loops tend to does positive work by the gas, while counterclockwise loops do negative work.

Given the cycle shown, what is the total work done by the gas during the cycle? A. -10 J B. 0 J C. 7.5 J D. 17.5 J

The point where the three wires connect exhibits no acceleration, meaning that no net forces are acting on it. T1: The force of gravity acting on the weight is equal to 10 N. Since T1 is below the stationary point, it will be pulled in the direction the weight is being pulled. T1 = 10 N downward. T2 & T3: Draw the x- and y-components of T2 and T3. X-components: cosθ = adjacent/hypotenuse cos(30) = T3x/T3 T3 * cos(30) = T3x cos(60) = T2x/T2 T2 * cos(60) = T2x Since we know the net force in the x-direction is zero: T2x = T3x meaning... T3 * cos(30) = T2 * cos(60) T3 * sqrt(3)/2 = T2 * 1/2 T3 * sqrt(3)/2 - T2 * 1/2 = 0 Y-components: Since the downward pull is 10 N, then the upward pull will equal 10 N as well. T3y + T2y = 10 N sinθ = opposite/hypotenuse sin(30) = T3y/T3 T3 * sin(30) = T3y sin(60) = T2y/T2 T2 * sin(60) = T2y Since the sum of the two y-components equals 10 N upwards, then... T2 * sin(60) + T3 * sin(30) = 10 N T2 * sqrt(3)/2 + T3 * 1/2 = 10 N For both equations: Multiply both equations by 2 to get rid of the denominators in both equations. x-component: 2 * (sqrt(3)/2 * T3 - 1/2 * T2 = 0) sqrt(3) * T3 - 1 * T2 = 0 sqrt(3) * T3 - T2 = 0 y-component: 2 * (T2 * sqrt(3)/2 + T3 * 1/2 = 10 N) T2 * sqrt(3) + T3 * 1 = 20 N T2 * sqrt(3) + T3 = 20 N Now multiply the y-component by sqrt(3) to match things up with x-components: sqrt(3) * (T2 * sqrt(3) + T3 = 20 N) T2 * 3 + T3 * sqrt(3) = 20 * sqrt(3) N Now subtract the y-component from the x-component: sqrt(3) * T3 - T2 = 0 - sqrt(3) * T3 + 3 * T2 = 20 sqrt(3) -4 * T2 = -20 sqrt(3) T2 = 5 sqrt(3) N Now we plug the value we have found for T2 into the x-component equation to find the value of T3: sqrt(3) * T3 - 5 sqrt(3) N = 0 sqrt(3) * T3 = 5 sqrt(3) N T3 = 5 N Answers: T1 = 10 N T2 = 5 sqrt(3) N T3 = 5 N

Given the shown diagram, find the force of tension in wires T1, T2, and T3.

Internal energy of a system increases when heat is added or work is being done on the system. Internal energy of a system decreases when heat is removed or work is being done by the system.

How can internal energy of a system be increased? How about decreased?

The only force acting in both motions is gravity.

How do the forces acting in free fall and projectile motion differ?

IAI IBI * cosθ = A x B

How do we calculate the cross product of vector multiplication?

IAI IBI * sinθ = A * B

How do we calculate the dot product of vector multiplication?

Use the formula: Q = m*c*ΔT Q = heat lost or gained m = mass of the object c = specific heat of the object ΔT = change in temperature of that object (Tf - Ti)

How do we determine the heat gained or lost by an object when the temperature of the object changes?

Use this formula: Q = m * L Q = heat of phase change m = mass of the object L = heat of transformation (fusion/vaporization

How do we determine the heat needed for an object to undergo a phase change

We use the dot product of the two vectors: A * B = IAI IBI * sinθ

How do we generate a scalar quantity when multiplying two vector quantities?

We use the cross product of the two vectors: A x B = IAI IBI * cosθ Then use the right hand rule to find the direction of the new vector.

How do we generate a vector quantity when multiplying two vector quantities?

1. Draw a right triangle, with the vector functioning as the hypotenuse. The vector components will function as the other two sides of the triangle. 2. Use the angle of the vector to find the magnitude of the vector components. SOH CAH TOA sinθ = opposite/hypotenuse cosθ = adjacent/hypotenuse

How do you break down a vector into two vector components?

1. If there is an instance where velocity does not change, then the formula for average velocity will result in instantaneous velocity. v = x/t 2. If velocity is changing, velocity can be found by looking at a line on a displacement vs. time graph. The slope at any particular point on the graph will equal the instantaneous velocity at that point in time. 3. If acceleration is constant, you can use the following kinematic formula to find instantaneous velocity at any given time: v = vi + at

How do you find instantaneous velocity without resorting to calculus?

1. Place the tail of one vector to the head of the other vector, without changing magnitude or direction. 2. Draw a hypotenuse from the tail of the first vector to the head of the second vector. 3. Use the Pythagorean theorem to find the magnitude of the hypotenuse. (A^2 + B^2 = C^2)

How do you find the total magnitude of two vectors?

A - B = A + (-B) -B has same magnitude as B, but in an opposite direction. Or subtract x & y components of one vector from another vector.

How does one subtract two vectors?

When rocket fuel combusts, the nozzle directs a hot river of gas at ultra high velocities. The force of these gases flowing out will act on the rocket, pushing it into the air by the high acceleration it is exhibiting.

How does rocket fuel cause a rocket to take-off?

Dot product A * B = IAI IBI * cosθ

How is a scalar calculated from the product of two vectors?

Cross product A x B = IAI IBI * sinθ

How is a vector calculated from the product of two vectors?

Compression is characterized by an increase in pressure and a decrease in volume. Expansion is characterized by an increase in volume and a decrease in pressure.

How is compression and expansion characterized in a PV diagram?

ΔL = αLΔT ΔL = change in length of solid α = coefficient of linear expansion L = original length ΔT = change in temperature

How is linear thermal expansion calculated?

ΔS = Q(rev)/T ΔS = change in entropy of a system Q(rev) = heat gained or lost in a reversible process T = temperature in Kelvin

How is the change in entropy of a system calculated?

Fg(Parallel) = m * a(g) * sinθ or Fg(Parallel) = Fg * sinθ Fg = force of gravity Fg(Parallel) = parallel component of the force of gravity m = mass of object a(g) = acceleration due to gravity θ = angle of incline

How is the parallel component of the force of gravity calculated on an incline plane?

Fg(Perpendicular) = m * a(g) * cosθ or Fg(Perpendicular) = Fg * cosθ Fg = force of gravity Fg(Perpendicular) = perpendicular component of force of gravity m = mass of object a(g) = acceleration due to gravity θ = angle of incline

How is the perpendicular component of the force of gravity calculated on an incline plane?

ΔV = βVΔT ΔV = change in volume β = coefficient of volumetric expansion V = original volume ΔT = change in temperature.

How is volumetric thermal expansion calculated?

W = PΔV W = work P = pressure ΔV = change in volume

How is work defined in a PV diagram for a thermodynamic process?

1 cal = 4.184 J

How many joules are in a calorie (cal)?

Q = m*c*ΔT m = 2 kg = 2000 g c = 4.184 J/g*K Tf = 50°C Ti = 20°C Q = 2000 g * 4.184 J/g*K * (50°C - 20°C) Q = 8368 J/K * 30 K Q = 251040 J

How much heat is needed to heat a 2 kg tank of water from a temperature of 20°C to 50°C? (Specific heat of water is 4.184 J/g*K)

Answer: D. Q = mcΔT m = 500 g = 0.5 kg c = 126 J/kg*K ΔT = 1064°C - 25°C = 1039 K Q = 0.5 kg * 126 J/kg*K * 1039 K Q = 65457 J Q(fus) = m * L(fus) m = 0.5 kg L(fus) = 6.37 x 10^4 J/kg Q(fus) = 0.5 kg * 6.37 x 10^4 J/kg Q(fus) = 31850 J 65457 J + 31850 J = 97307 J = 97 kJ

How much heat is required to completely melt 500 g gold earrings, given that their initial temperature is 25°C? (The melting point of gold is 1064°C, its heat of fusion is 6.37 x 10^4 J/kg, and its specific heat is 126 J/kg*K) A. 15 kJ B. 32 kJ C. 66 kJ D. 97 kJ

Red = Isobaric Yellow = Isothermal Green = Adiabatic Blue = Isochoric

Identify the types of thermodynamic processes shown on the PV diagram.

v = x/t t = 1 minute = 60 seconds v = 5 m/s 5 m/s = x/60 s x = 5 m/s * 60 s = 300 m x = 300 m to the south

If Marcia travels 1 minute at 5 m/s to the south, how much will she be displaced?

v = displacement/time = x/t displacement (x) = 5 km = 5000 m time (t) = 1 hour = 3600 seconds v = 5000 m/3600 s = 1.39 m/s v = 1.39 m/s north

If Shantanu was able to travel 5 km north in 1 hour in his car, what was his average velocity?

2nd Same

If a brick is floating in space, then Newton's __________ Law tells us that if we apply a net force to one side of the brick, then you will have a net acceleration going in the __________________ direction.

s = d/t d = 10 m + 10 m + 10 m + 10 m = 40 m t = 30 seconds s = 40 m/30 s = 1.33 m/s

If a car travels 10 meters north, then 10 meters east, then 10 meters south, and then 10 meters west in the span of 30 seconds, what is the average speed?

v = x/t x = 0 m, since the change in position of the car has not changed t = 60 seconds v = 0 m/60 s = 0 m/s

If a car travels 15 meters north, then 15 meters east, then 15 meters south, and then 15 meters west in the span of 60 seconds, what is the average velocity?

It will rotate on its center of mass.

If a force acts on the ruler to the right of the center of mass, what will happen to the ruler?

Move in the direction of the force and with appropriate acceleration. Rotate around the center of mass.

If a force is applied to the center of mass of an object, the object will _________________________. If force is applied away from the center of mass of an object, the object will __________________________.

Unbalanced To the left

If a force pushes on a rock from the left side, then am stronger force pushes the rock from the right side, will result in the forces acting on the rock being _________________________. This means that the rock's movement will be ________________________.

Balanced Not moving

If a force pushes on a rock from the left side, then an equal force pushes the rock from the right side, will result in the forces acting on the rock being _________________________. This means that the rock's movement will be ________________________.

Unbalanced To the right

If a force pushes on a rock from the right side, then am stronger force pushes the rock from the left side, will result in the forces acting on the rock being _________________________. This means that the rock's movement will be ________________________.

A straight line A straight horizontal line

If acceleration is constant, then the line on a velocity vs time graph will be _______________________. If velocity is constant, then the line on a velocity vs time graph will be __________________________.

Terminal velocity Free fall

If an object falls at a constant acceleration due to gravitational force, the object will never reach _____________________. This is known as __________________.

Geometric center

If an object has a uniform distribution (it is made out of the same substance and the density of the substance does not change throughout the object), the center of mass will be the object's ________________________________.

The velocity of the object would change, it would either be accelerating or decelerating.

If an object is being acted on by an unbalanced force, what would be the movement of that object?

It will either be at rest or moving at a constant velocity.

If an object is being acted on by balanced forces, what would be the movement of that object.

Negative Positive

If an object is rotating clockwise around the center of mass or fulcrum, then torque will be _____________________. If an object is rotating counterclockwise around the center of mass or fulcrum, then torque will be ___________________________.

Answer: C. The Kelvin unit and Celsius degree are the same size; that is, a change of 10 K is equal to a change of 10°C. One degree Celsius is equal to 1.8 degrees Fahrenheit; therefore, 10°C = 18°F.

If an object with an initial temperature of 300 K increases its temperature by 1°C every minute, by how many degrees in Fahrenheit will its temperature increased in 10 minutes? A. 6°F B. 10°F C. 18°F D. 30°C

Negative Slowing down

If an object's velocity decreases numerically, its acceleration is _______________, meaning the object is ___________________.

Positive Speeding up

If an object's velocity increases numerically, its acceleration is ______________, meaning the object is ___________________.

No, it is possible to force heat from a cold object to a hot object, but not spontaneously. It requires work to actually do this.

If heat flows from a colder object to a hotter object in thermal contact, does this disobey the second law of thermodynamics?

It will either be moving at a constant velocity or at rest.

If no forces are acting on an object, what would be the movement of that object?

Changed directions

If the line in a velocity vs time graph crosses the x-axis, then that means the object has __________________________.

constant constant

If the line on a velocity vs time graph is straight, the slope is ________________, and the acceleration is ___________________.

Not accelerating At rest Moving at a constant velocity

If the resultant force on an object is zero, the object is _______________________________, meaning it is either _________________ or __________________________________.

Zero

If the velocity of an object is constant, then the acceleration of the object will be ______________________.

F = ma F = 10 N m = 2 kg 10 N = 2 kg * a 5 m/s^2 = a

If we have a force of 10 N acting on a mass of 2 kg. What is the acceleration?

F = ma F = 20 N m = 2 kg 20 N = 2 kg * a a = 10 m/s^2

If we have a force of 20 N acting on a mass of 2 kg, what is the acceleration?

F = ma F = 20 N m = 4 kg 20 N = 4 kg * a a = 5 m/s^2

If we have a force of 20 N acting on a mass of 4 kg, what is the acceleration

an unbalanced force

If we have a rock laying on a field of grass, that rock will not move unless ___________________________ is applied to the rock.

The center of mass will be closer to the side that is made of lead, since it is more dense than Styrofoam.

If we have a square where the left side is made of Styrofoam and the right side is made of lead, where would be the center of mass for this square?

Place the fulcrum about a fourth of the way across the lever, with the fulcrum being closer to the object. This will result in a 3:1 ratio of lever arms, meaning only 1/3 of the original force will be needed.

If you have an object three times as heavy as you can lift, how could a lever be used to lift the object? Where would the fulcrum need to be placed?

It will exert a net force on your hand that is equal in magnitude, but opposite in direction. As a result, your hand will become compressed by the force exerted by the block.

If you try to push a block forward with your hand, what will the block do?

The amount of heat added did not exceed the amount needed to completely melt the block of ice: Q = mL m = 200 g L = 333 J/g Q = 200 g * 333 J/g = 6.66 x 10^4 Heat used is 5.46 x 10^4 J Therefore, no heat was applied to change the temperature of the resulting liquid and T remains constant. ΔS = Q(rev)/T Q(rev) = 5.46 x 10^4 J T = 273 K ΔS = 5.46 x 10^4 J/273 K = 200 J/K ΔS = 200 J/K

If, in a reversible process, 5.46 x 10^4 J of heat is used to change a 200 g block of ice to water at a temperature of 273 K, what is the change in entropy of the system? (Note: Heat of fusion for ice is 333 J/g)

translational equilibrium rotational equilibrium

In _______________________ equilibrium, the object is either at rest or is moving at a constant velocity. In ________________________ equilibrium, the object is either rotating at a constant angular velocity, or is not rotating at all.

If the volume decreases (compression), it means that work is being done on the system. Thus, work will be positive.

In a PV diagram, if the curve shows a decrease in volume, what does that say about the work being exerted?

If the volume increases (expansion), it means that work is being done by the system. Thus, work will be negative.

In a PV diagram, if the curve shows an increase in volume, what does that say about the work being exerted?

Velocity would equal to the slope of the graph. m = y/x v = x/t

In a displacement vs time graph, how is velocity determined?

Speed would equal to the slope of the graph. m = y/x s = d/t

In a distance vs time graph, how is speed determined?

Gravitational force constant Gravitational force

In a one-dimensional kinematic problem, assuming air resistance is negligible, the only force that will be acting on an object falling is _________________________. Because of this, the object will fall at a ______________________ acceleration, which is from _________________________.

Gravitational force Air resistance Speed Greater Increases Drag force Weight Terminal velocity

In a one-dimensional kinematic problem, if air resistance is not negligible, then ___________________ will be pushing the object down while _____________________ will oppose the motion of the object falling. The value of air resistance increases as the ___________________ of the object increases. When air resistance is not negligible, then an object in free fall will experience a ________________ drag force as the magnitude of its velocity _________________. When ___________________ becomes equal in magnitude to the ______________ of an object, the object will fall at a constant velocity, known as ____________________.

Greater Smaller

In a velocity vs time graph, a steeper slope results in a _____________________ acceleration, while a less-steep slope results in a ____________________ acceleration.

Acceleration would equal to the slope of the graph. m = y/x a = v/t

In a velocity vs time graph, how is acceleration determined?

positive negative

In a velocity vs time graph, velocity is __________________________ if the line is above the x-axis, and is _________________________ if the line is below the x-axis.

Zero Positive Negative

In a velocity vs time graph: If the slope of the line is equal to zero, then the acceleration is _____________________. If the slope of the line is positive, then the acceleration is ___________________. If the slope of the line is negative, then the acceleration is _______________________.

Answer: B. To understand this question, make sure you understand all the terms. An adiabatic process means that there is no exchange of heat; in other words, Q = 0. When a gas is compressed, positive work is being done on the gas (instead of by the gas), so the value of work done on the gas will be positive (W > 0). Based on this, we can determine how the internal energy of the gas changes by using the first law of thermodynamics (ΔU = Q + W) If Q = 0, and W is positive, then ΔU is positive.

In an adiabatic compression process, the internal energy of the gas: A. increases, because the work done on the gas is negative. B. increases, because the work done on the gas is positive. C. decreases because the work done on the gas is negative. D. decreases because the work done on the gas is positive.

Tangent

In circular motion, the instantaneous velocity vector is always ________________ to the circular path.

Answer: B. When the ink randomly intersperses throughout the water, the final state is more disordered than the initial state, so the entropy change of the system is positive. When the oil separates from the water, the final state is just as ordered as the initial state (because the oil and the water are still completely separate), so the entropy change is zero. You can also answer this question by noticing the reversibility of the two experiments. Experiment A has a positive entropy change because it is irreversible, while experiment B has no entropy change because the reaction is reversible. According to the second law of thermodynamics, the overall entropy change of a system and its surroundings can never be negative in a thermodynamic process that moves from one equilibrium state to another.

In experiment A, a student mixes ink with water and notices that the two liquids mix evenly. In experiment B, the student mixes oil with water; in this case, the liquids separate into two different layers. The entropy change is: A. positive in experiment A and negative in experiment B B. positive in experiment A and zero in experiment B C. negative in experiment A and positive in experiment B D. zero in experiment A and negative in experiment B.

The force of gravity on an object.

In physics, weight is usually determined by __________________________________________.

Vx = V * cosθ V = velocity of an object Vx = horizontal velocity θ = angle of elevation

In projectile motion, how do you find the horizontal velocity of an object (regardless of it being initial, average, or final)?

Vy = V * sinθ V = velocity of an object Vy = vertical velocity θ = angle of elevation

In projectile motion, how do you find the vertical velocity of an object (regardless of it being initial, average, or final)?

Coefficient of static friction (μ(s)) Coefficient of kinetic friction (μ(k))

In static and kinetic friction of an object, the maximum value of _____________ will always be greater than the constant value of ______________.

Positive heat implies that heat is being added to the system. Negative heat implies that heat is being removed from the system.

In the equation for the First Law of Thermodynamics, what is the difference of heat being positive vs. heat being negative.

Positive work implies that work is being done on the system, and thus internal energy is added to the system. Negative work implies that work is being done by the system, and thus internal energy is removed from the system.

In the equation for the First Law of Thermodynamics, what is the difference of work being positive vs. work being negative?

Slowing Down

In the following graph, is the object speeding up or slowing down?

Slowing down

In the following graph, is the object speeding up or slowing down?

Speeding Up

In the following graph, is the object speeding up or slowing down?

Speeding up

In the following graph, is the object speeding up or slowing down?

Accelerating Moving in the negative direction (opposite of initial velocity)

In the graph, is the object accelerating or decelerating? What is the direction the object is moving in?

Accelerating Moving in the positive direction (same direction of initial velocity)

In the graph, is the object accelerating or decelerating? What is the direction the object is moving in?

Decelerating Moving in the negative direction (opposite of initial velocity)

In the graph, is the object accelerating or decelerating? What is the direction the object is moving in?

Decelerating Moving in the positive direction (same direction of initial velocity)

In the graph, is the object accelerating or decelerating? What is the direction the object is moving in?

Velocities Accelerations Horizontal Vertical

In two-dimensional kinematics problems, ______________________ and _________________ of the two directions (usually ______________ and ____________________) are independent of each other and must be analyzed separately.

Zero

In uniform circular motion, tangental force is equal to ________________, since the speed of the object is constant.

No, typically the coefficient of static friction is greater than the coefficient of kinetic friction. It always requires more force to get an object to start sliding than it takes to keep an object sliding. μ(k) < μ(s)

Is the coefficient of kinetic friction greater than the coefficient of static friction?

Constant, positive velocity

Motion described as _____________________ velocity results in a line of zero slope.

Gravity Frictional forces Electrostatic forces Magnetic forces Elastic forces Weak nuclear forces Strong nuclear forces

Name two forces in addition to mechanical manipulation (pushing or pulling forces created by contact with an object).

Galileo's law of inertia

Newton's first law is essentially a restatement of _______________________________________.

kg * m/s^2

Newtons is a derived unit based off of ___________________.

vertical vertical velocity horizontal velocity

Objects in projectile motion (on Earth) experience the force of acceleration of gravity only in the __________________ direction. This means that acceleration due to gravity will affect _______________________, but _________________________ will remain constant.

The slope of the line on the graph is equal to the velocity of the object.

On a displacement vs time graph, how is velocity of an object determined?

The slope of the line on the graph is equal to the acceleration of the object.

On a velocity vs time graph, how is acceleration of an object determined?

There are two ways of solving this problem: Method 1: Solve using a kinematic formula x = Va * Δt 0s - 3s: Va = (40 m/s + 0 m/s)/2 = 20 m/s Δt = 3 seconds - 0 seconds = 3 seconds x = 20 m/s * 3 s = 60 m 3s - 6s: Va = 40 m/s (since the velocity is constant) Δt = 6 seconds - 3 seconds = 3 seconds x = 40 m/s * 3 s = 120 m 6s - 10s: Va = (40 m/s + 0 m/s)/2 = 20 m/s Δt = 10 seconds - 6 seconds = 4 seconds x = 20 m/s * 4 s = 80 m Add up all the displacements: x = 60 + 120 + 80 = 260 m Method 2: Find the area under the line on the graph base = time height = velocity 0s - 3s: Area looks like triangle, so use geometric formula for the area of a triangle 1/2 * 3 * 40 = 60 m 3s - 6s: Area looks like rectangle, so use geometric formula for the area of a rectangle 3 * 40 = 120 m 6s - 10s: Area looks like triangle, so use geometric formula for the area of a triangle 1/2 * 4 * 40 = 80 m Add the areas together: 60 + 120 + 80 = 260 m Regardless of which method is used, total displacement is 260 m. x = 260 m

Say a car was driving in the span of 10 seconds. It speeds up from 0 m/s to 40 m/s in 3 seconds, maintains that velocity for 3 more seconds, then hits the breaks and slows to a stop in 4 seconds. The velocity vs time graph recorded the velocity the car exhibited during that 10 seconds. Using the information given, what is the total displacement of the car in 10 seconds?

a) d = 1/2 * a * t^2 + Vo * t t = 4 seconds a = 2 m/s^2 Vo = 5 m/s d = 1/2 * 2 m/s^2 * (4 s)^2 + 5 m/s * 4 s d = 16 m + 20 m d = 36 m b) Vf = Vo + a * t Vo = 5 m/s a = 2 m/s^2 t = 4 s Vf = 5 m/s + 2 m/s^2 * 4 s Vf = 5 m/s + 8 m/s Vf = 13 m/s

Say an object was moving at an initial velocity of 5 m/s. The object speeds up at a constant acceleration of 2 m/s^2 for 4 seconds. a) How far did the object travel? b) How fast was the object going after 4 seconds?

First convert miles/h to miles/s 60 miles/h * 1 hour * 1 min = 0.017 miles/s 60 min 60 s a = Δv/Δt Δv = 0.017 miles/s - 0 miles/s = 0.017 miles/s Δt = 3 s - 0 s = 3 s a = 0.017 miles/s/3 s = 0.0056 miles/s^2

Say that a Porsche 911 is able to go from 0 to 60 mph in 3 seconds due east. What is its acceleration?

First convert km/h to m/s: 97 km/h * 1000 m * 1 hour * 1 min = 26.94 m/s 1 km 60 min 60 s a = Δv/Δt Δv = 26.94 m/s - 0 m/s = 26.94 m/s Δt = 3 s - 0 s = 3 s a = 26.94 m/s/3 s = 9 m/s^2 (actual = 8.98 m/s^2)

Say that a Porsche 911 is able to go from 0 to 97 km/h in 3 seconds due east. What is its acceleration?

Unbalanced Movement will change

Say that a person is pushing a block across a floor, and a person who is stronger than the other person pushed the block in the opposite direction. Is the force balanced or unbalanced?

Balanced Movement will not change

Say that a person is pushing a block across a floor, and a person with the same strength as the first person pushed the block in the opposite direction. Is the force balanced or unbalanced? Would the movement of the block change?

τ = F x d τ = F * d * sinθ θ = 90° d = 10 m F = 5 N = 5 kg * m/s^2 τ = 5 N * 10 m * sin(90°) τ = 5 N * 10 m * 1 τ = 50 N * m

Say that a plank of wood is nailed to a wall at a particular point. You push on the plank with a force of 5 N to make it rotate counterclockwise. The distance between the nail and where the force is applied is 10 m, and force is applied at a 90° angle. What would the magnitude of the torque applied to the ruler be?

Since we are finding thermal equilibrium: Q(Cu) + Q(H2O) = 0 Q(Cu) = m*c*ΔT m = 0.5 kg = 500 g c = 0.387 J/g*K Ti = 90°C = 363 K Q(H2O) = m*c*ΔT m = 2 kg = 2000 g c = 4.184 J/g*K Ti = 20°C = 293 K Q(Cu) = 500 g * 0.387 J/g*K * (Tf - 363 K) Q(H2O) = 2000 g * 4.184 J/g*K * (Tf - 293 K) Q(Cu) = 193.5 J/K * (Tf - 363 K) Q(H2O) = 8368 J/K * (Tf - 293 K) Q(Cu) = 193.5 J/K * Tf - 70240.5 J Q(H2O) = 8368 J/K * Tf - 2451824 J (193.5 J/K * Tf - 70240.5 J) + (8368 J/K * Tf - 2451824 J) = 0 8561.5 J/K * Tf - 2522064.5 J = 0 8561.5 J/K * Tf = 2522064.5 J Tf = 294.58 K or 21.58°C

Say that we have a 2 kg container filled with water, sitting at a temperature of 20°C. If we were to drop a 0.5 kg block of copper with a temperature of 90°C into the water, what would be the temperature of thermal equilibrium that both the copper and water will reach. (Specific heat of copper = 0.387 J/g*K) (Specific heat of water = 4.184 J/g*K)

Q = mcΔT m = 2 kg = 2000 g c = 4.184 J/gK Tf = 100°C Ti = 20°C Q = 2000 g * 4.184 J/gK * (100°C - 20°C) Q = 669440 J Q(vap) = m * L(vap) m = 2000 g L(vap) = 2260 J/g Q(vap) = 2000 g * 2260 J/g Q(vap) = 4520000 J 669440 J + 4520000 J = 5189440 J

Say that we have a container of water that contains 2 kg of water and is sitting at a temperature of 20°C. How much heat do we need to add if we want to vaporize the water into steam? (Specific heat of water = 4.184 J/g*K) (Boiling point of water = 100°C) (Heat of vaporization for water = 2260 J/g)

Vy = opposite Vx = adjacent V = hypotenuse V = 5 meters θ = 36.8699° sinθ = opposite/hypotenuse sin(36.8699°) = Vy/5 m 5 * sin(36.8699°) = 3 m = Vy cosθ = adjacent/hypotenuse cos(36.8699°) = Vx/5 m 5 * cos(36.8699°) = 4 m = Vx

Say that we have a vector that has a magnitude of 5 meters and an angle of 36.8699° in respect to the x-axis. What are the magnitudes of the vector components?

sinθ = opposite/hypotenuse sin(30°) = Vy/10 m 10 * sin(30°) = 5 * j^ = Vy cosθ = adjacent/hypotenuse cos(30°) = Vx/10 m 10 * cos(30°) = 8.66 * i^ = Vx V^2 = Vx^2 + Vy^2 V^2 = (8.66 * i^)^2 + (5 * j^)^2 V^2 = 75 (i^)^2 + 25 (j^)^2 V = sqrt(100 (i^)^2 + (j^)^2) V = 10 i^ + j^

Say that we have a vector with a magnitude of 10 meters and an angle of 30°. Find the vector in unit vector notation.

Newton's third law states that for every action, there is always an equal, but opposite reaction. With this in mind, you must take the most massive thing that you are carrying at the time, and throw that object in the opposite direction. By throwing an object in that direction, you are exerting force on that object, which also leads to the object exerting an equal and opposite force on you, which will cause you to accelerate in the opposite direction that the object was thrown.

Say that you are an astronaut in space, and you are drifting away in space when you lose connection from the shuttle. Assuming you have no jet pack on you to propel you back to the shuttle. How do you use Newton's third law to avoid drifting off into space?

Insulate the container, so that there is no transfer of heat into or out of the system. Move the piston up and down extremely fast, to make sure no heat escapes the container.

Say that you have a cylindrical container full of a gas, a piston is at the top of the container, and the container is sitting on a heating plate. With this set up, how can we make an adiabatic process in a lab?

By having the piston move freely. This allows the volume of the chamber to increase and decrease in accordance with heat being added or removed, while maintaining a constant pressure.

Say that you have a cylindrical container full of a gas, a piston is at the top of the container, and the container is sitting on a heating plate. With this set up, how can we make an isobaric process in a lab?

Have the piston fixated in a certain position. This allows for the heat to increase and decrease the pressure in the system without actually changing the volume.

Say that you have a cylindrical container full of a gas, a piston is at the top of the container, and the container is sitting on a heating plate. With this set up, how can we make an isochoric process in a lab?

Either push or pull the piston very slowly. This way, the heat always has time to enter or exit the system accordingly, allowing for the temperature to remain constant.

Say that you have a cylindrical container full of a gas, a piston is at the top of the container, and the container is sitting on a heating plate. With this set up, how can we make an isothermal process in a lab?

Q = mcΔT m = 1 kg c = 233 J/kg*K ΔT = 962°C - 20°C = 924 K Q = 1 kg * 233 J/kg*K * 924 K Q = 219486 J Q(fus) = mL m = 1 kg L = 1.05 x 10^5 J/kg Q(fus) = 1 kg * 1.05 x 10^5 J/kg Q(fus) = 105000 J Q(total) = Q + Q(fus) Q(total) = 219486 J + 105000 J = 324486 J Q(total) = 324486 J

Silver has a melting point of 962°C and a heat of fusion of approximately 1.05 x 10^5 J/kg. The specific heat of silver is 233 J/kg*K. Approximately how much heat is required to completely melt a 1 kg silver chain with an initial temperature of 20°C.

Distance/Time Meters/Second

Speed is measured as _______________/_________________ usually in _________/__________.

a = Δv/Δt Δv = 15 m/s Δt = 0.2 s a = 15 m/s/0.2 s = 75 m/s

Suppose you are golfing, and you hit the ball on the tee with your club. At 0.2 seconds, the ball is travelling with a velocity of 15 m/s. What is the acceleration of the ball?

Answer: D. Saying that substance B has a higher internal energy cannot explain the phenomenon because the internal energy is irrelevant; the heat involved in the process is related only to the specific heat, the heat of fusion, and the heat of vaporization. All of the other choices could explain the phenomenon. The heat required to melt the solid is determined by the heat of fusion, (C). The heat required to bring the liquid to its boiling point is determined by the specific heat, (A). The heat required to boil the liquid is determined by the heat of vaporization (B).

Substances A and B have the same freezing and boiling points. If solid samples of both substances are heated in the exact same way, substance A boils before substance B. Which of the following would not explain this phenomenon? A. Substance B has a higher specific heat B. Substance B has a higher heat of vaporization C. Substance B has a higher heat of fusion D. Substance B has a higher internal energy

ΔV = βVΔT β = 1.8 x 10^-4 K^-1 V = 1 mL ΔT = 275°C - (-25°C) = 300 K ΔV = 1.8 x 10^-4 K^-1 * 1 mL * 300 K ΔV = 0.054 mL

Suppose that a thermometer with 1 mL of mercury is taken from a freezer with a temperature of -25°C and placed near an oven at 275°C. If the coefficient of volume expansion of mercury is 1.8 x 10^-4 K^-1, by how much will the liquid expand?

-3 i^ + 2 j^ + 2 i^ + 4 j^ -1 i^ + 6 j^ R^2 = a^2 + b^2 R^2 = (-1 i^)^2 + (6 j^)^2 R^2 = 1 (i^)^2 + 36 (j^)^2 R^2 = 37 (i^ + j^)^2 R = sqrt(37 (i^ + j^)^2) R = 6.1 i^ + j^

Suppose we have two vectors: a = -3 i^ + 2 j^ b = 2 i^ + 4 j^ Find the resultant vector of these two vectors.

2 i^ + 3 j^ + 10 i^ + 2 j^ 12 i^ + 5 j^ R^2 = a^2 + b^2 R^2 = (12 i^)^2 + (5 j^)^2 R^2 = 144 (i^)^2 + 25 (j^)^2 R^2 = 169 (i^ + j^)^2 R = sqrt(169 (i^ + j^)^2) R = 13 i^ + j^

Suppose we have two vectors: a = 2 i^ + 3 j^ b = 10 i^ + 2 j^ Find the resultant vector of these two vectors.

Newtons (N) kg * m/s^2

The SI units used for force is _________________________ which is equivalent to _____________________.

MKS metric system

The _________________ metric system is represented in meters, kilograms, and seconds.

CGS metric system

The __________________ metric system is represented in centimeters, grams, and seconds.

Instantaneous Instantaneous Average Average

The __________________________ speed of an object will always equal to the ________________________ velocity of an object. However, the ______________________ speed of an object will not always equal to the _______________________ velocity of an object.

90 degrees minus the degree angle of the incline.

The angle that is formed between the Fg vector and the parallel component of the Fg vector is equal to _________________________________________.

The degree angle of the incline plane

The angle that is formed between the Fg vector and the perpendicular component of the Fg vector is equal to _________________________________________.

How much denser one substance is compared to the other.

The center of mass in an object consisting of 2 different materials will depend on _________________________________.

Lever arm

The distance between the fulcrum and the applied forces on an object is known as the _____________________.

Answer: B. The entropy of a system can decrease as long as the entropy of its surroundings increases by at least as much. On the other hand, the entropy of an isolated system increases for all (irreversible) processes. This adheres to the second law of thermodynamics, which says that energy will be dispersed and entropy of the universe will remain constant or increase during all processes.

The entropy of a system can: A. never decrease. B. decrease when the entropy of the surroundings increases by at least as much. C. decrease when the system is isolated and the process is irreversible. D. decrease during an adiabatic reversible process.

Answer: C. In this situation, heat will transfer from the warm gas to the metal and then to the cold gas. Convection requires flow of a fluid to cause heat transfer, invalidating (B) as an answer. In this case, the gas is not flowing, but rather is in contact with the metal. (A) is an invalid answer because heat transfer through radiation, is also implausible not only because gases are unlikely to emit heat in the form of waves, but also because the radiation would be unlikely to penetrate the thick metal containers, Enthalpy, (D), is not a form of heat transfer. Conduction, (C), is the most likely option; it happens when two substances make direct contact with one another. Here, gas A makes contact with the metal container, which makes contact with gas B.

The figure shown depicts a thick metal container with two compartments. Compartment A is full of a hot gas, while compartment B is full of a cold gas. What is the primary mode of heat transfer in this system? A. Radiation B. Convection C. Conduction D. Enthalpy

instantaneous velocity v = instantaneous velocity vi = initial velocity a = acceleration t = time

The following kinematic formula can be used to determine ______________________ if acceleration is constant: v = vi + at v = _______________________ vi = ______________________ a = _______________________ t = ________________________

Newton (N)

The unit of measurement for force is _______________________.

1. Draw a free body diagram that shows the forces acting on the tire. 2. Split the forces into x- and y-components x-components: The person at the bottom is pulling the rope in a vertical direction, meaning that he does not have an x-component. (x-component = 0 N) For the person pulling the rope up-left: cosθ = adjacent/hypotenuse cos(37) = Fx/F F = 125 N cos(37) = 0.8 125 N * 0.8 = Fx Fx = 100 N For the person pulling the rope up-right cos(30) = Fx/F F = 100 N cos(30) = 0.866 100 N * 0.866 = Fx Fx = 86.6 N Fx(net) = 86.6 N - 100 N = -13.4 N 13.4 N to the left y-components: For the person at the bottom, they are pulling the rope vertically, so they only have a y-component. (y-component = 125) For the person pulling the rope up-left: sinθ = opposite/hypotenuse sin(37) = Fy/125 N 125 N * 0.6 = Fy Fy = 75 N For the person pulling the rope up-right: sin(30) = Fy/100 N 100 N * 0.5 = Fy Fy = 50 N Fy(net) = 50 N + 75 N - 125 N = 0 N Net force will be 13.4 N to the left. No net forces acting in the y-direction

Three people are pulling on ropes tied to a tire with forces of 100 N, 125 N, and 125 N as shown. Find the magnitude and direction of the net force. (Note: sin(30) = 0.5, cos(30) = 0.866, sin(37) = 0.6, cos(37) = 0.8)

Work Perpendicular Parallel Work

Torque has the same type of unit of measurement as _______________________ (N * m). The difference between the two is that distance and force are __________________ in torque, while distance and force are __________________ in _____________________.

True An unbalanced force is the net force acting on the object. So the object will accelerate in the direction of the net force.

True or False An object acted on by an unbalanced force will always accelerate in the direction of the unbalanced force.

True Object will not move if no forces are acting upon the object or if the forces acting on the object is balanced.

True or False An object at rest will stay at rest unless acted on by an unbalanced force.

True This statement is in accordance with Newtons first law of motion.

True or False An object in motion will maintain its speed and direction forever unless acted on by an unbalanced force.

False Seems consistent with everyday life; however, if we do not account for any of the other minor forces that interferes with the velocity of an object, then the object will continue to move at a constant velocity unless acted upon.

True or False An object in motion will slow down unless it is acted on by an unbalanced force in the direction of motion.

False Mass and weight are not the same measurement. Mass is a measure of the amount of matter in an object, while weight is the measure of gravitational force on an object's mass.

True or False Mass and weight represent the same measurement.

False According to Newton's 3rd law, forces are always reciprocal in nature. When the Earth exerts a force on a person, the person also exerts a force of the same magnitude on the Earth (in the opposite direction).

True or False The Earth creates a larger force on you than you create on the Earth.

False If an unbalanced force is applied to the same direction as the object's movement, direction will not change. An unbalanced force can change the direction of a moving object, but this is not always the case.

True or False. An unbalanced force on an object will always change the object's direction.

False An unbalanced force on the body will always impact the object's VELOCITY, not speed. Speed is the magnitude of velocity; while an unbalanced force usually does change the speed, this is not always the case.

True or False. An unbalanced force on the body will always impact the object's speed.

True If an object was moving through a space at a constant velocity with no forces acting on it, then the velocity will not change.

True or False. If the net force on a body is zero, its velocity will not change.

True Forces like friction, air resistance, and gravity are responsible for why objects do not continue to move at a constant velocity in our everyday life.

True or False. The reason why initially moving objects tend to come to a rest in our "everyday" life is because they are being acted on by an unbalanced force.

False. This would be true of an addition problem in which both vectors have equal magnitude, but it is never true for vector multiplication. To find the direction of C, we must use the right-hand rule. If the thumb points in the direction of A, and the fingers point in the direction of B, then our palm, C, points out of the page.

True or false. If C = A x B, where A is directed towards the right side of the page and B is directed to the top of the page, then C is directed mid-way between A and B at a 45° angle?

True, displacement considers the most direct route between two points. Distance will always be equal or larger in magnitude than displacement.

True or false: Total distance traveled can never be less than the total displacement.

1. Find force of gravity on block A Fg = m * a(g) m = 15 kg a(g) = 9.8 m/s^2 Fg = 15 kg * 9.8 m/s^2 Fg = 147 N 2. Find normal force acting on block A F(N) = F(g) in opposite direction F(N) = 147 N opposite of gravity 3. Find force of static friction on block A F(s) = μ(s) * F(N) F(N) = 147 N μ(s) = 0.2 F(s) = 0.2 * 147 N F(s) = 29.4 N 4. Find the force of tension on the string Since the two blocks are in equilibrium, that means F(s) = F(t) in opposite direction F(t) = 29.4 N 5. Find force of gravity acting on block B Since the two blocks are in equilibrium, that means F(t) = Fg in opposite direction Fg = 29.4 N 6. Find mass of block B Fg = m * a(g) Fg = 29.4 N a(g) = 9.8 m/s^2 29.4 N = m * 9.8 m/s^2 29.4 N/9.8 m/s^2 = m m = 3 kg

Two blocks are in static equilibrium, as shown. If block A has a mass of 15 kg and the coefficient of static friction between block A and the surface is 0.2. What is the maximum mass of block B?

Displacement/Time Meters/Second

Velocity is measured as _____________/______________ usually in ____________/____________.

Process functions are thermodynamic properties that describes the path taken to get from one state to another. Heat (Q) Work (W)

What are process functions? List the different types of process functions.

Gravity Electrostatic forces between point charges

What are some examples of forces that exists between two objects that are not close to one another?

-Tension -Gravity -Electrostatic forces -Normal forces

What are some forces that causes centripetal force?

Linear thermal expansion Volumetric thermal expansion

What are some ways in which heat can alter the physical properties of matter.

State functions are thermodynamic properties of a system that are a function of only the current equilibrium state of a system. Pressure (P) Density (ρ) Temperature (T) Volume (V) Enthalpy (H) Internal energy (U) Gibbs free energy (G) Entropy (S)

What are state functions? List the different types of state functions.

Meter (m) - Length Kilogram (kg) - Mass Seconds (s) - Time Ampere (A) - Current Mole (mol) - Amount of substance Kelvin (K) - Temperature Candela (cd) - Luminous intensity

What are the 7 SI units?

1. Kinetic friction is constant for any given combination of coefficient of kinetic friction and normal force (thus the equation uses an equal sign). Static friction is not constant for any given combination of coefficient of kinetic friction and normal force (thus the equation uses a less than or equal to sign). 2. Coefficients of friction are different for each equation. Value of μs is always larger than the value of μk.

What are the differences between static friction and kinetic friction?

Since the A vector is oriented to the x-direction and the B vector is oriented in the y-direction, θ = 90°. A x B = IAI IBI * sinθ A x B = 3 N * 4 m * sin(90°) = 3 * 4 * 1 = 12 N*m If we use the right hand rule, vector C will be pointing into the page. B x A = IBI IAI * sinθ B x A = 4 m * 3 N * sin(90°) = 4 * 3 * 1 = 12 N*m If we use the right hand rule, vector D will be pointing out of the page.

What are the magnitudes and directions of the resultant vectors from the following cross products: C = A x B D = B x A A: X = -3 N Y = 0 B: X = 0 Y = 4 m

-Conduction -Convection -Radiation

What are the three methods of which heat can transfer energy?

Static friction Kinetic friction

What are the two types of friction?

By adding or removing heat from the system By doing work on the system or having work be done by the system

What are the two ways to change the internal energy of a system?

An object moving at constant velocity will continue moving at constant velocity, and an object at rest will still be at rest, unless it is acted on by a net unbalanced force. F = ma = 0

What does Newton's first law of motion state?

An object with a given mass will accelerate when the sum of all forces acting upon it will result in a non-zero resultant force vector. F = ma

What does Newton's second law of motion state?

To every action, there is always an equal and opposite reaction, or the forces of two bodies on each other are always equal and directed in opposite directions. F(AB) = -F(BA)

What does Newton's third law of motion state?

There are more microstates for a disordered macrostate than there are microstates for an ordered macrostate. (There are more possibilities for microstates in a macrostate where energy is mixed than there are possibilities for microstates in a macrostate where energy is separated to one side over the other).

What does entropy say about the macrostates and microstates of a system?

It is moving in the direction of the initial velocity It is moving in the opposite direction of the initial velocity

What does it mean for an object to be moving at a positive velocity? What does it mean for an object to be moving at a negative velocity?

i-hat represents a vector component moving along the x-axis j-hat represents a vector component moving along the y-axis

What does the i-hat and j-hat represent in unit vector notation.

The entropy of the universe is constantly increasing. ΔS(universe) = ΔS(system) + ΔS(surroundings) > 0

What does the second law of thermodynamics claim about the entropy of the universe?

There will be no net flow of heat between the two objects, since they are in thermodynamic equilibrium.

What happens when two objects at the same temperature make thermal contact with one another.

Heat will flow from the warmer object to the cooler object.

What happens when two objects of differing temperatures make thermal contact with one another?

The new vector will either be parallel (if the scalar is positive) or antiparallel (if scalar is negative) to the old vector.

What happens when you multiply a vector by a scalar?

A thermodynamic process in which no heat is neither added nor removed from the system.

What is an adiabatic thermodynamic process?

A thermodynamic process in which the pressure of the system does not change.

What is an isobaric thermodynamic process?

A thermodynamic process in which the volume of the system does not change.

What is an isochoric thermodynamic process?

A thermodynamic process in which the temperature in the system does not change, and by extension, the internal energy of the system does not change.

What is an isothermal thermodynamic process?

It is the amount of spontaneous dispersal of energy at a certain temperature in a system. The disorderliness of energy in a system.

What is entropy?

a = Δv/Δt a = acceleration Δv = change in velocity Δt = change in time

What is the formula for finding the acceleration of a moving object?

A constant that characterizes how a specific material's length changes as temperature changes. A constant that characterizes how a specific material's volume changes as temperature changes. The coefficient of volumetric expansion is equal to three times the coefficient of linear expansion. (β = 3α)

What is the coefficient of linear expansion? What is the coefficient of volumetric expansion? What is the relationship between the two?

The difference in thermal/kinetic energy between two objects that determines the direction heat will flow.

What is the definition of temperature at a macroscopic level?

The average kinetic energy of the particles in a certain substance.

What is the definition of temperature at a molecular level?

Newton (N) = kg*m/(s^2) Dyne = g*cm/(s^2)

What is the derived unit of force in the MKS metric system? In the CGS metric system?

Watt (W) = kg*(m^2)/(s^3) Erg/second = g*(cm^2)/(s^3)

What is the derived unit of power in the MKS metric system? In the CGS metric system?

Joule (J) = kg*(m^2)/(s^2) Erg = g*(cm^2)/(s^2)

What is the derived unit of work and energy in the MKS metric system? In the CGS metric system?

A macrostate describes the general conditions of a system, like if it is organized or disorganized. A microstate describes the specific details within a given macrostate.

What is the difference between a macrostate and a microstate?

A natural process would describe the transfer of energy from a hot object to a cold object. An unnatural process would describe the transfer of energy from a cold object to a hot object.

What is the difference between a natural thermodynamic process and an unnatural thermodynamic process?

A reversible process would result in a net change in entropy of zero between the system and its surroundings. An irreversible process would result in a net increase in entropy between the system and its surroundings.

What is the difference between a reversible thermodynamic process and an irreversible thermodynamic process?

State functions are variables independent from the path taken to achieve a particular equilibrium and are properties of a given system at equilibrium; they may be dependent on one another. Process functions define the path (or how the system got to its state) through variables such as Q (heat) or W (work).

What is the difference between a state function and a process function?

Isolated system: A system in which matter and energy cannot enter or exit the system. Closed system: A system in which energy can freely enter and exit, but matter cannot. Open system: A system in which matter and energy can freely enter and exit the system.

What is the difference between an open system, a closed system, and an isolated system?

Instantaneous speed refers to the speed at a particular point in time, while average speed is the average of the speed values given over a span of time.

What is the difference between average speed and instantaneous speed?

Instantaneous velocity refers to the velocity at a particular point in time, while average velocity is the average of the velocity values given over a span of time.

What is the difference between average velocity and instantaneous velocity?

0 km, since the change in position is no different from when we started.

What is the displacement of a man who walks 2 km east, then 2 km north, then 2 km west, and then 2 km south?

ΔU = Q + W ΔU = change in internal energy of a system Q = heat added to the system W = work done on the system (-W if work is done by the system)

What is the equation that describes the First Law of Thermodynamics.

Fc = m * v^2/r Fc = centripetal force m = mass v = speed r = radius of the circular path

What is the equation used to calculate centripetal force/circular motion?

F(g) = m * a(g) F(g) = Force of gravity (weight) m = mass of object a(g) = acceleration due to gravity

What is the equation used to calculate the weight of an object?

F(g) = (G * m1 * m2)/(d^2) F(g) = Force of gravity between two objects G = Universal gravitational constant (6.67 x 10^-11 N * m^2/kg^2) m1 = mass of first object m2 = mass of second object d = distance between the two centers of mass

What is the equation used to determine the gravitational force between two different objects?

F(k) = μ(k) * F(N) F(k) = kinetic friction μ(k) = coefficient of kinetic friction F(N) = Normal force

What is the equation used to determine the kinetic friction of a moving object?

F(k) = μ(k) * F(N) F(k) = Kinetic friction μ(k) = coefficient of kinetic friction F(N) = Magnitude of normal force

What is the equation used to determine the kinetic friction of an object?

F(s) < μ(s) * F(N) F(s)max = μ(s) * F(N) F(s) = static friction F(s)max = maximum static friction in a stationary object μ(s) = coefficient of static friction F(N) = Normal force

What is the equation used to determine the static friction of a stationary object?

F(s) < μ(s) * F(N) F(s) = Static friction μ(s) = coefficient of static friction F(N) = Magnitude of normal force

What is the equation used to determine the static friction of an object?

τ = F x d = d * F * sinθ Torque is a cross product vector F = force acting perpendicularly to the lever arm d = distance of the force from the pivot point (lever arm) θ = angle formed between the lever arm and the force vectors

What is the equation used to determine the torque of a rotating object?

Answer: C. Q = mcΔT Q = 100W/10 min (Watts is equal to Joules per second, so Joules will equal Watts times seconds) 100 W * 10 min * 60 s = 60000 J Q = 60000 J m = 3 kg c = 500 J/kg*K Ti = 20°C 60000 J = 3 kg * 500 J/kg*K * (Tf - 20°C) 60000 J = 1500 J/K * (Tf - 20°C) 40°C = Tf - 20°C Tf = 60°C

What is the final temperature of a 3 kg wrought iron fireplace tool that is left in front of an electric heater, absorbing heat energy at a rate of 100 W for 10 minutes? Assume the tool is initially at 20°C and that the specific heat of wrought iron is 500 J/kg*K. A. 40°C B. 50°C C. 60°C D. 70°C

When an object is thrown, the object will rotate around a single point within the object, being the center of mass, while that point will move in a simple parabolic pathway.

What occurs when you throw an object in regards to its center of mass?

Condensation

What type of phase change involves transitioning from a gas to a liquid?

Deposition

What type of phase change involves transitioning from a gas to a solid?

Boiling/evaporation/vaporization

What type of phase change involves transitioning from a liquid to a gas?

Freezing/solidification/crystallization

What type of phase change involves transitioning from a liquid to a solid?

Sublimation

What type of phase change involves transitioning from a solid to a gas?

Melting/fusion

What type of phase change involves transitioning from a solid to a liquid?

The work is represented by the area underneath the curve. W = P*ΔV

When looking at a PV diagram, how do you determine the work done by the gas? What is the equation that represents this area?

Lighter Heavier

When accelerating in an elevator, you feel ________________________. When decelerating in an elevator, you feel ____________________________.

zero

When an object has reached its maximum height, its velocity will equal _________________________.

slowing down

When an object's velocity decreases in magnitude (numerical value), regardless of being above or below the x-axis, the object is _______________________.

speeding-up

When an object's velocity increases in magnitude (numerical value), regardless of being above or below the x-axis, the object is _______________________.

If two objects are in thermal contact with each other, and there is no net heat flow between the two objects, then they are in thermal equilibrium.

When are two objects in thermal equilibrium?

The direction of the frictional force is always opposed to movement. Once the net force is known, the frictional force must be opposite of that direction.

When calculating frictional forces, how is directionality assigned?

Vector subtraction, like vector multiplication, is not a commutative function. The resultant of A - B has the same magnitude as B - A, but is oriented in the opposite direction.

When calculating the difference of vectors A and B (A-B) we invert B and put the tail of this new vector at the tip of A. What would be the effect of reversing this order (B-A)?

Vector addition, unlike vector multiplication, is a commutative function. The resultant of A + B is the same as B + A, so there would be no difference between the two resultants.

When calculating the sum of vectors A and B (A+B) we put the tail of B at the tip of A. What would be the effect of reversing this order (B+A)?

For a closed system, entropy increases when thermal energy is distributed into the system at a given temperature. Likewise, entropy decreases when thermal energy is distributed out of a system at a given temperature.

When does entropy increase for a closed system? When does it decrease?

Constant If there is no net force acting on an object, then that object is not experiencing an acceleration and it has a constant velocity.

When no force is being applied, the velocity of an object must be ______________________.

Answer: C. In SI units, mass is measured in kilograms (kg), velocity in meters per second (m/s), and time in seconds (s). The newton is a derived unit, and is not considered to be a base unit of the SI system. A newton is equal to a kg*m/(s^2).

Which of the following expressions correctly illustrates the SI base units for each of the variables in the formula below? mΔv = FΔt A. lb * mph = ft * lb * s B. kg * m/s = N * s C. kg * m/s = kg*m/(s^2) * s D. g * m/s = g*m/(s^2) * s

The center of mass will be directly in the center of the triangle, with equal distance away from each of the angles.

Where would be the center of mass of the triangle shown?

Answer: A. Because there is essentially only empty space between the Sun and the Earth, the only means of heat transfer is by radiation - electromagnetic waves that propagate across space. When a metal spoon is placed in a pot of hot soup, the molecules in the soup collide with those on the surface of the spoon, thereby transferring heat by conduction. Finally, fire warms the air above it, and the warmed air is less dense than the surrounding air, so it rises. A rising column of warm air means that heat is being transported in the air mass, which is simply the process of convection. The smoke particles ride along with the upward moving air current and create a plume of smoke.

Which of the following choices correctly identifies the following three heat transfer processes? I. Heat transferred from the Sun to the Earth II. A metal spoon heating up when placed in a pot of hot soup III. A rising plume of smoke from a fire A. I. Radiation, II. Conduction III. Convection B. I. Conduction II. Radiation III. Convection C. I. Radiation II. Convection III. Conduction D. I. Convection II. Conduction III. Radiation

Answer: B. State functions are any that are independent of the path taken to achieve a given state and which are not themselves defined as a process, such as pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy. Heat and work are process functions that are pathway dependent.

Which of the following is not a state function? A. Internal energy B. Heat C. Temperature D. Entropy

Answer: C. If a substance is undergoing a phase change, any added heat will be used toward overcoming the heat of transformation of the phase change. During the phase change, the temperature will remain constant. Temperature is a measure of the kinetic energy of the molecules in a sample, so a change in kinetic energy (A) is essentially the same thing as a change in temperature. The heat transfer by radiation described in (B) will definitely change the temperature of the solid as long as it is not in the process of melting. (D) Describes heat transfer by convection, in which the warm gas will transfer heat to the cold gas until they both reach an intermediate temperature.

Which of the following processes is least likely to be accompanied by a change in temperature? A. The kinetic energy of a gas is increased through a chemical reaction B. Energy is transferred to a solid via electromagnetic waves C. A boiling liquid is heated on a hot plate D. A warm gas is mixed with a cool gas

Answer: D. A vector is characterized by both magnitude and direction. From the given answer choices, all are vectors except for distance. Distance is a scalar because it has only a numerical value and lacks direction.

Which of the following quantities is not a vector? A. Velocity B. Force C. Displacement D. Distance

Answer: B. The presence of friction does not change the impact of Newton's laws. A net force must still be applied to cause motion. This net force is not necessarily equal to an applied force, as friction and gravity also acts on the object; thus, statement I is eliminated. Static friction opposes the movement of stationary objects, and is necessarily greater than the force of kinetic friction; thus statement II is correct. Statement III is false because the normal force is related to mass, and friction is related to the normal force.

Which of the following statements is true of movement on a plane with friction? I. Acceleration is a function of applied force only II. More force is needed to accelerate a stationary object than an identical moving object III. The force of friction is independent of the mass of objects A. I only B. II only C. I and II only D. I and III only

Gases are considered the worst heat conductors because of the amount of space that exists between gas particles. This space between individual molecules causes energy-transferring collisions to occur relatively infrequently.

Why are gases considered to be the worst heat conductors?

Metals are the best heat conductors because of the free movement of electrons in metals due to metallic bonds. This sea of electrons allows for rapid energy transfer in metals.

Why are metals considered to be the best heat conductors?

The average velocity is equal to the ratio of displacement over the change in time Δx/Δt, while average speed is the ratio of the total distance traveled over a change of time Δd/Δt.

Why is average speed not always equal to average velocity?

Because of how high the specific heat of water is, it is able to absorb a lot of heat, and barely change that much in temperature.

Why is water often considered a great heat exchanger?

ΔU = Q + W Work is done on the gas: W = +60 J Heat is lost: Q = -150 J ΔU = 60 J - 150 J ΔU = -90 J

You have a certain gas in a cylindrical container with a piston at the top of it. 60 J of work is being done on the gas, and the gas loses 150 J of heat to its surrounding. What is the change in internal energy?

ΔU = Q + W Work done by the gas: W = -70 J Heat is added: Q = 180 J Ui = 200 J Uf - 200 J = 180 J - 70 J Uf - 200 J = 110 J Uf = 310 J

You have a certain gas in a cylindrical container with a piston at the top of it. A gas starts with 200 J of internal energy. While you add 180 J of heat to the gas, the gas does 70 J of work. What is the final internal energy of the gas?

ΔU = Q + W Work is done on the gas: W = 40 J ΔU = -150 J -150 J = Q + 40 J Q = -190 J

You have a certain gas in a cylindrical container with a piston at the top of it. While 40 J of work is done on the gas, the internal energy goes down by 150 J. What was the value of the heat added to the gas?

Circular motion

______________ is a form of motion that occurs when forces causes an object to move in a circular pathway.

Speed

_______________ is the scalar quantity that measures how fast an object is moving.

Radiation

_______________ is the transfer of energy in the form of electromagnetic waves, and is capable of transferring energy through a vacuum.

Instantaneous velocity

________________ is a vector quantity that measures the change in position, including the direction of its change in position, of an object at a particular moment in time.

Mass Weight

________________ is the amount of a given substance there is. _____________ is how much mass is being pulled down by gravity.

Heat

________________ is the transfer of thermal energy from an object with higher temperature/energy to an object with lower temperature/energy.

Velocity

________________ is the vector quantity that measures the change in position, including the direction of its change in position, of an object.

Instantaneous speed

_________________ is a scalar quantity that measures how fast an object is moving at a particular moment in time.

Weight

_________________ is a vector quantity of the measure of gravitational force on an object's mass.

Work

_________________ is the process by which energy is transferred as a result of force being applied through a certain distance.

Thermodynamics

_________________ is the study of energy, the conversion of energy between different forms, and the ability for energy to do work.

Mass

__________________ is a scalar quantity of the measure of the amount of matter in an object.

Friction

__________________ is a type of force that opposes the movement of objects.

Centripetal acceleration

__________________ is the acceleration of an object that travels in a circle; it is always directed towards the center of the circle if the object is in uniform circular motion.

Acceleration

__________________ is the change of velocity over a period of time.

Torque

__________________ is the force applied at a distance away from the pivot point (fulcrum) or center of mass.

Conduction

__________________ is the transfer of energy through the collision of molecules between two objects that are in direct contact with one another.

Convection

__________________ is the transfer of heat due to the bulk movement of molecules in a fluid (liquid or gas), where hot molecules rise to the top of the fluid while cool molecules fall to the bottom of the fluid.

Specific heat

__________________ refers to the amount of heat energy necessary to raise one gram of a substance by one degree/unit Celsius/Kelvin.

Gravity

____________________ is an attractive force that is felt by all forms of matter.

Tension

____________________ is the force that exists either within or applied by a string of wire when lifting something or pulling something.

Distance

_____________________ is a scalar quantity that represents the pathway that an object has traveled.

Deceleration

_____________________ is the acceleration in the opposite direction of initial velocity.

Dynamics

_____________________ is the study of forces and torques.

Normal force

_______________________ is the force perpendicular to a surface that prevents an object from falling through the surface.

Fg(parallel) Fg(perpendicular)

_______________________ represents the component vector of the force of gravity that is parallel to the surface. _______________________ represents the component vector of the force of gravity that is perpendicular to the surface.

centripetal force

________________________ is a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.

Displacement

________________________ is a vector quantity representing the straight-line distance and direction from an initial point; not necessarily equal to total distance traveled, and measured in meters.

Static friction

________________________ is the friction that exists between a stationary object and the surface upon which it rests on.

Center of mass

_________________________ is the point in an object that acts as if the entire mass of an object was concentrated at that point.

Uniform circular motion Nonuniform circular motion

__________________________ is circular motion in which the object's speed is constant. __________________________ is circular motion in which the object's speed is not constant.

Translational equilibrium Rotational equilibrium

_____________________________ equilibrium can only exist when the vector sum of all the forces acting on an object is equal to zero. ____________________________ equilibrium can only exist when the vector sum of all torques acting on an object is equal to zero.

Kinetic friction

_____________________________ is the friction that exists between a sliding object and the surface over which the object slides on.

Translational motion Rotational motion

_______________________________ motion occurs when forces cause an object to move without any rotation. ________________________________ motion occurs when forces cause an object to rotate on a center of mass or a fulcrum.

cos(30) = sqrt(3)/2 cos(60) = 1/2 cos(45) = 1/sqrt(2) cos(90) = 0 cos(0) = 1 sin(30) = 1/2 sin(60) = sqrt(3)/2 sin(45) = 1/sqrt(2) sin(90) = 1 sin(0) = 0

cos(30) = ________________ cos(60) = ________________ cos(45) = ________________ cos(90) = ________________ cos(0) = __________________ sin(30) = ________________ sin(60) = ________________ sin(45) = ________________ sin(90) = _______________ sin(0) = ________________

cos(30) = sqrt(3)/2 or 0.866 cos(60) = 1/2 or 0.5 cos(45) = 1/sqrt(2) or 0.707 cos(90) = 0 cos(0) = 1 sin(30) = 1/2 or 0.5 sin(60) = sqrt(3)/2 or 0.866 sin(45) = 1/sqrt(2) or 0.707 sin(90) = 1 sin(0) = 0

cos(30) = ________________ cos(60) = ________________ cos(45) = ________________ cos(90) = ________________ cos(0) = __________________ sin(30) = ________________ sin(60) = ________________ sin(45) = ________________ sin(90) = _______________ sin(0) = ________________

sinθ = opposite/hypotenuse cosθ = adjacent/hypotenuse tanθ = opposite/adjacent Remember: SOH CAH TOA

sinθ = ________________________ cosθ = ______________________ tanθ = ________________________