Physics Final
What is the term for the net force directed toward the center of an object's circular path?
Centripetal force
In this text, what does the symbol u represent?
Coefficient of kinetic friction.
Which of the following forces arises from direct physical contact between two forces?
Contact force
Why s air resistance considered a form of friction?
Cuz it moves in the opposite direction yo.
In the figure above, the magnitude of the ball's velocity is greatest at location
D
The graph above describes the motion of a ball. At what point is the velocity of the ball equal to its velocity at B?
D
Where should a force be applied on a lever arm to produce the most torque?
Farthest from the axis of rotation
Objects that are falling toward Earth in free fall move
Faster and faster
Which of the following equations expresses Newton's law of universal gravitation?
Fg = G(m1m2 / r2)
The Newton is the SI unit of what physical quantity?
Force
What causes a moving object to change direction?
Force
Which of the following is the cause of an acceleration?
Force
Which of the following statements does not describe force?
Force causes objects at rest to remain stationary.
Briefly describe how applying the brakes to stop a bicycle is an example of force.
Force in opposite direction in motion
How does the force of static friction on a crate you cannot budge compare to the force you exert on it? Assume that the crate is on a flat surface.
Forces are equal magnitude but in opposite directions.
When a falling object reaches terminal speed (where the acceleration on the object is zero), what is the relationship between Fr, the force of air resistance on the object and Fg?
Forces are equal magnitudes in opposite directions.
Which of the following is a coordinate system for specifying the precise location of objects in space?
Frame of reference
Acceleration due to gravity is also called
Free-fall acceleration
Which of the following confirms that gravitational mass and inertial mass are equal
Free-fall acceleration is the same at all points where the gravitational strength is the same.
What kind of force provides the centripetal force on the bicycle?
Friction
In this text, which of the following symbols represents the constant of universal gravitation?
G
Which of the following is a form of mechanical energy?
Gravitational potential energy
A block of wood supported by two concrete blocks is chopped in half by a karate instructor. Identify an action-reaction pair, and compare the forces exerted by each object.
Guy exerts chopping force on the wood, wood exerts a chopping force on the karate instructor.
Which of the following statements applies to the motion of a ball rising and then falling in free fall?
I, II, and III.
In the figure above, which diagram represents the vector addition C = A + B
II
In the figure above, which diagram represents the vector subtraction C = A - B
IV
In the equation Fnet = ma, what is the direction of the acceleration?
In the direction of Fnet
In what direction does the force of air resistance act?
In the opposite direction of the force.
The centripetal force on an object in circular motion is
In the plane of the object's motion and perpendicular to the tangenital speed.
What happens to air resistance when an object accelerates?
Increases
After colliding, objects are deformed and lose kinetic energy. Identify the type of collision.
Inelastic
A ball is whirled on a string, then the string breaks. What causes the ball to move off in a straight line?
Inertia
When a car makes a sharp left turn, what causes the passengers to move toward the right side of the car?
Inertia
Which of the following is the tendency of an object to maintain its state of motion?
Inertia
Suppose you are given a position versus time grap. The slope of a line drawn tangent to a point on the curve of this graph describes what quantity?
Instantaneous velocity
The graph above describes the motion of a cyclist. The graph illustrates that the acceleration of the cyclist
Is constant
A negative acceleration generally indicates that an object
Is slowing down
A billiard ball collides with a stationary identical billiard ball in an elastic head-on collision. After the collision, which of the following is true of the first ball?
It comes to rest.
Why is force not a scalar quantity?
It has a direction
A car is traveling at 20 m/s and experiences an acceleration of -0.25 m/s&2. What happens to its motion?
It slows down.
How would the speed of Earth's orbit around the sun change if Earth's distance form the sun increased by 4 times?
It would decrease by a factor of 2.
How would the speed of Earth's orbit around the sun change if Earth's distance from the sun increased by 4 times?
It would decrease by a factor of 2.
Which of the following are not units of power?
J
Which of the following formulas would be used to directly calculate the kinetic energy of an object with mass m bouncing up and down on a spring with spring constant k?
KE = 1/2mv^2
Why doesn't the principle of mechanical energy conservation hold in situations when frictional forces are present?
Kinetic energy is not completely converted to a form of potential energy.
The length of the force vector is proportional to what property of a force?
Magnitude
Which of the following units is the SI unit of velocity?
Meter per second, m/s
Which of the following statements about the conservation of momentum is not correct?
Momentum is not conserved for a system of objects in a head-on cllision.
A passenger on a bus moving east sees a man standing on a curb. from the passenger's perspective, the man appears to
Move west at a speed that is equal to the bus's speedd
Which of the following best describes the momentum of two bodies after a two-body collision if the kinetic energy of the system is conserved?
Must also be conserved
What is the abbreviation of the unit newton?
N
What are the units for a spring constant?
N/m
In the graph above, what is the correct description of any location to the left of the zero?
Negative position
When a ball is thrown down with an initial velocity of +10 m/s, what should we use for the acceleration?
+9/8 m/s^2
A rock is thrown upward with an initial velocity of 10 m/s. What will be its velocity as it returns to the person's hand?
- 10 m/s
Ball A has triple the mass and speed of ball B. What is the ratio of kinetic energy to ball A to ball B.
27
Which of the following situations is an example of a visible change in momentum?
A baseball is hit by a bat.
In which of the following scenarios is work done?
A car decelerates while traveling on a flat stretch of road.
In which of the following scenarios is no net work done?
A car travels at a constant speed on a flat road.
Which of the following situations represents a negative displacement? (Assume positive position is measure vertically upward along a y-axis.)
A cat jumps from a tree limb to the ground.
Which of the following does not exhibit parabolic motion?
A flat piece of paper released from a window.
Which of the following is not an example of projectile motion?
A hot-air balloon drifting toward Earth
Which of the following statements properly relates the variables in the equation change in p = F * change in t?
A large constant force acting over a large time interval causes a large change in momentum.
What is the path of a projectile (in the absence of friction)?
A parabola
If a force is exerted on an object, which statement is true?
A small force applied over a long time interval can produce a large change in the object's momentum.
For which of the following situations is the conservation of mechanical energy most likely to be a valid assumption?
A soccer ball flies through the air.
Which of the following exhibits parabolic motion?
A stone thrown into a lake
Which of the following situations is an example of a significant change in momentum?
A tennis ball is hit into a net.
Which of the following is an example of projectile motion?
A thrown baseball
Which of the following line segments on a position versus time graph is physically impossible?
A vertical line
Acceleration is defined as
The rate of change of velocity
How would the speed of Earth's orbit around the sun change if Earth's mass increased by 4 times?
The speed would not change.
A hockey stick hits a puck on the ice. Identify an action-reaction pair in this situation.
The stick exerts a force on the puck; the puck exerts a force on the stick.
In the equation form of newton's second law, EF = ma, what does EF represent?
The sum of all external forces - summation
Which would fall with greater acceleration in a vacuum - a leaf or a stone?
They would accelerate at the same rate.
Which would hit the ground first if dropped from the same height in a vacuum - a feather or a metal bolt?
They would hit the ground at the same time
The statement by Newton that for every action there is an equal but opposite reaction is which of his laws of motion?
Third
What is the natural tendency of an object that is in motion?
To stay in motion
Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis?
Torque
Which of the following is a true statement about the conservation of energy?
Total energy is always conserved.
Suppose a doorknob is placed at the center of a door. Compared with a door whose knob is located at the edge, what amount of force must be applied to this door to produce the torque exerted on the other door?
Two times as much
If you cannot exert enough force to loosen a bolt with a wrench, which of the following should you do?
Use a wrench with a longer handle.
Which of the following is an equation for average velocity?
Vavg = change in distance (x) / change in time (t)
Which of the following is a physical quantity that has both magnitude and direction?
Vector
The quantity, 0.5 km/s west is a
Velocity
Which of the following is an example of a vector quantity?
Velocity
When a car is moving, what happens to the velocity and acceleration of the car if the air resistance becomes equal to the force acting in the opposite direction?
Velocity is equal, acceleration is 0.
Which of the following line segments on a velocity versus time graph are physically impossible?
Vertical line
A football player runs in one direction to catch a pass, then turns and runs twice as fast in the opposite direction toward the goal line. Which of the following is a correct expression for the original velocity and the resulting velocity?
Vplayer, -2Vplayer
What is the common formula for work? Assume that W is the work, F is a constant force, change in V is the change in velocity, and d is the displacement
W = Fd
Distinguish between mass and weight
W =gravity, M = matter
How do mass and weight vary with altitude?
Weight changes, mass does not.
In the graph above, a toy rolls from +3 m to +5 m. Which of the following statements is true?
Xi = +3m (Initial distance = +3m)
A free-body diagram of a ball falling in the presence of air resistance would show
a downward arrow to represent the force due to gravity and an upward arrow to represent the force of air resistance
Gravitational potential energy is always measured in relation to
a zero level.
In a coordinate system, a vector is oriented at angle theta with respect to the x-axis. the x component of the vector equals the vector's magnitude multiplied by which trigonometric function?
cos theta
Which displacement vectors shown in the figure have vertical components that are equal?
d1 and d3
A 75 kg person walking around a corner bumped into an 80 kg person who was running around the same corner. The momentum of the 80 kg person
decreased.
A 20 kg shopping cart moving at a velocity of 0.5 m/s collides with a store wall and stops. The momentum of the shopping cart
decreases.
Tides are caused by
differences in the gravitational force of the moon at different points on Earth.
In a coordinate system, the magnitude of the x component of a vector and theta, the angle between the vector and x-axis, are known. the magnitude of the vector equals the x component.
divided by the cosine of theta
Which form of energy is involved in weighing fruit on a spring scale?
elastic potential energy
In the figure above, the horizontal component of the ball's velocity at A is
equal to the horizontal component of its initial velocity
A free-body diagram represents all of the following except
forces exerted by the object
When calculating the gravitational force between two extended bodies, you should measure the distance
from the center of each body
As a basketball player starts to jump for a rebound, the player begins to move upward and faster and faster until his shoes leave the floor. At the moment the player begins to jump, the force of the floor on the shoes is
greater than the player's weight
In the figure above, according to Kepler's law of planetary motion
if change in t1 is equal to the change in t2, then a1 is equal to a2
The centripetal force on an object in circular motion is
in the same direction as the centripetal acceleration
An object's tendency to resist acceleration is measured by the object's
inertial mass
As a ball rolls up a hill, its forward positive velocity decreases. The ball comes to a stop and then rolls back down the hill with increasing velocity. Ignoring gravity, the ball's acceleration
is always negative.
When an object is moving with uniform circular motion, the object's tangenital speed
is constant
When an object is moving with uniform circular motion, the centripetal acceleration of the object
is directed toward the center of motion
A roller coaster climbs up a hill at 4 m/s and then zips down the hill at 30 m/s. The momentum of the roller coaster
is greater down the hill than up the hill.
A force does work on an object if a component of the force
is parallel to the displacement of the object.
What are the SI units for momentum?
kg * m/s
A newton is equivalent to which of the following quantities?
kg * m/s^2
Which of the following energy forms is associated with an object in motion?
kinetic energy
The main difference between kinetic energy and potential energy is that
kinetic energy involves motion, and potential energy involves position
Describe the forces acting on a car as it moves along a level highway in still air at a constant speed
lol idk
Why does it require much less force to accelerate a low-mass object than it does to accelerate a high-mass object the same amount?
lol idk
Construct a free-body diagram of a car being towed
lol physics is phun
What is the SI unit of acceleration?
m/s^2
The length of a force vector represents the
magnitude of the force
A measure of the quantity of matter is
mass
Which of the following refers to the sum of kinetic energy and all forms of potential energy?
mechanical energy
The impulse experienced by a body is equivalent to the body's change in
momentum
In a two-body collision,
momentum is always conserved.
Friction converts energy to
nonmechanical energy
In the presence of frictional force,
nonmechanical energy is no longer negligible and mechanical energy is no longer conserved.
Which of the following equations can be used to directly calculate an object's momentum, p?
p = mv
Which of the following energy forms is associated with an object due to its position?
potential energy
Which of the following is the rate at which work is done?
power
Which of the following is the rate at which energy is transferred?
powr
Which of the following parameters does not depend on how resistant a spring is being compressed or stretched?
relaxed length
A rubber ball moving at a speed of 5 m/s hit a flat wall and returned to the thrower at 5 m/s. The magnitude of the momentum of the rubber ball
remained the same.
A soccer ball collides with another soccer ball at rest. The total momentum of the balls
remains constant.
In a coordinate system, a vector is oriented at angle theta with respect to the x-axis. The y component of the vector equals the vector's magnitude multiplied by which trigonometric function?
sin theta
What term describes a change in the speed of an object in circular motion?
tangential acceleration
Which statement about the acceleration of an object is correct?
the acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the mass of the object.
If the sign of work is negative,
the displacement is in the direction opposite the force.
Work is done when
the displacement is not zero.
The free-body diagram shown above represents a car being pulled by a towing cable. In the diagram, the 5800 N force is
the force exerted by the towing cable on the car
If you lift an apple from the ground to some point above the ground, the gravitational potential energy in the system increases. This potential energy is stored in
the gravitational field between Earth and the apple.
If friction is the only force acting on an object during a given physical progress, which of the following assumptions can be made in regard to the object's kinetic energy?
the kinetic energy decreases.
Two objects with different masses collide and bounce back after an elastic collision. Before the collision, the two objects were moving at velocities equal in magnitude but opposite in direction. After the collision,
the less massive object had gained momentum.
In an inelastic collision between to objects with unequal masses,
the momentum of one object will increase by the amount that the momentum of the other object decreases.
When an astronaut in orbit experiences apparent weightlessness,
the net gravitational force on the astronaut is not balanced by a normal force.
According to Newton's second law, when the same force is applied to two objects of different masses,
the object with greater mass will experience a smaller acceleration, and the object with less mass will experience a greater acceleration
The change in an object's momentum is equal to
the product of the force applied to the object and the time interval.
A more powerful motor can do
the same work in a shorter time interval
The law of conservation of momentum states that
the total momentum of all objects interacting with one another remains constant regardless of the nature of the forces between the objects.
As an object falls toward Earth,
the upward acceleration of Earth is negligible because of its large mass.
Two skaters stand facing each other. One skater's mass is 60 kg, and the other's mass is 72 kg. If the skaters push away from each other without spinning,
their momenta are equal but opposite.
Two swimmers relax close together on air mattresses in a pool. One swimmer's mass is 48 kg, and the other's mass is 44 kg. If the swimmers push away from each other,
their momenta are equal but opposite.
Newton's third law of motion involves the interactions of
two objects and two forces
A billiard ball collides with a second identical ball in an elastic head-on collision. What is the kinetic energy of the system after the collision compared with the kinetic energy before the collision?
unchanged
Multiplying or dividing vectors by scalars results in
vectors
What information is implied in the following question? "A police car starts at rest to catch up with a speeder. How long will it take to travel 100 m with an acceleration of 2 m/s^2?"
vi = 0 m/s
A person sitting in a chair with wheels stands up, causing the chair to roll backward across the floor. The momentum of the chair
was zero while stationary and increased when the person stood.
A change in the gravitational force acting on an object will affect the object's
weight
The magnitude of the gravitational force acting on an object is
weight
Which of the following is the best coordinate system to analyze a painter climbing a ladder at an angle of 60 degrees to the ground?
x-axis: horizontal along the ground, y-axis: up and down.
A car goes forward along a level road at constant velocity. the additional force needed to bring the car into equilbirium is
zero
If a car goes from 62 kmhr to 36 km/hr in 10 seconds, what is its acceleration?
-3.6 m/s^2
A student walks from the door of the house to the end of the driveway and realizes he missed the bus. The student runs back to the house, traveling three times as fast. Which of the following is the correct expression for the return velocity if the initial velocity is Vstudent?
-3Vstudent
A ball with a momentum of 4.0 kg * m/s hits a wall and bounces straight back without losing any kinetic energy. What is the change in the ball's momentum?
-8.0 kg * m/s
A single force acts on an object. The components of this force act along the +x-axis and the -y-axis. The single force that will bring the object into equilibrium has components that act along the
-x-axis and +y-axis.
For an object to be in equilibrium, the net force acting on the object must have what value?
0
If two teams playing tug-of-war pull on a rope with equal but opposite forces, what is the net external force on the rope?
0
If the mass of a horizontal mass-spring system was doubled, the elastic potential energy in the system would change by a factor of
0 (no change)
A child moving at constant velocity carries a 2 N ice-cream cone 1 m across a level surface. What is the net work done on the ice-cream cone?
0 J
A worked does 25 J of work lifting a bucket, then sets the bucket back down in the same place. What is the total net work done on the bucket.
0 J
What is the speed of a ball at the top of its flight?
0 m/s
When a ball is dropped, what is its initial velocity?
0 m/s
When an object is moving at constant speed, what is its acceleration?
0 m/s^2
According to the graph above, during which interval does the cat have the greatest positive velocity?
0.0 - 5.0 s
What is the speed of an object at rest?
0.0 m/s
A car travels down a road at a certain velocity, vcar. The driver slows down so that the car is traveling only half as fast before. Which of the following is the correct expression for the result velocity?
1/2vcar
According to the graph above, the cat has the fastest speed during which interval?
10.0 - 15.0 s
Convert 1 g/cm^3 to kg/m^3
1000 kg/m^3
A bug moves 10 cm north, 2 cm south, then 5 cm north, what is its displacement?
13 cm north
The free-body diagram shown above represents a car being pulled by a towing cable. In the diagram, which of the following is the gravitational force acting on the car?
14700 N
How many displacement vectors shown in the figure above have components that lie along the y-axis and are pointed in the -y direction?
2
How many displacement vectors are shown in the figure above have horizontal components?
4
If the displacement of a horizontal mass-spring system was doubled, the elastic potential energy in the system would be a factor of
4
A dog runs 15 m west then 13 m east in 7 seconds, what is his average speed?
4 m/s
The gravitational force between two masses is 36N. What is the gravitational force if the distance between them is tripled?
4.0N
Two small masses that are 10.0 cm apart attract each other with a force of 10.0 N. When they are 5.0cm apart, these masses will attract each other with what force?
40.0N
In the free-body diagram shown above, which of the following is the gravitational force acting on the balloon?
4050 N
According to the graph above, during which interval is the cat at rest?
5.0 - 10.0 s
If Fnet = Fg, what is the magnitude and direction of the acceleration of the object? Assume that the object is on the Earth's surface.
9.8 m/s^2 downward.
Which of the following is an equation for acceleration?
Acceleration = change in velocity (v) / change in time (t)
Which are simultaneous equal but opposite forces resulting from the interaction of two objects?
Action-reaction pairs
If an object has a constant positive acceleration,
All of the above
If you know the acceleration of a car, its initial velocity, and the time interval, which of the following can you predict?
All of the above
Which of the following can be a centripetal force?
All of the above
Which of the following is in free fall?
An arrow that has been shot up in the air
State Newton's first law of motion
An object at rest will tend to stay at rest, an object in motion will tend to stay in motion unless acted upon by an external force.
If you want to open a swinging door with the least amount of force, where should you push on the door?
As far from the hinges as possible
A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity and nonzero at the same time?
At the top of its path.
At what point of the ball's path shown in the figure above is the vertical component of the ball's velocity zero?
B
In the figure above, the magnitude of the ball's velocity is least at location
B
In a free-body diagram of an object, why are forces exerted by the object not included in the diagram?
Because they do not change its motion
Two objects are dropped off the top of the Empire State Building. One has a mass of 10 kg and the other 100 kg. Which object will hit the ground first?
Both at the same time.
Two objects are dropped off the top of the Empire State Building. One has a mass of 10 kg and the other 100 kg. Which object will be going the fastest when it hits the ground?
Both have the same speed.
How are force vectors represented in force diagrams?
By arrows
In the figure above, at which point is the ball's speed about equal to the speed which it was tossed?
C
The graph above describes the motion of a ball. At what point does the ball have an instantaneous velocity of zero?
C
The graph above describes the motion of a ball. At what point is the speed of the ball equal to its speed at B?
C
The motion of a ball on an inclined plane is described by the equation displacement = 1/2(a*t)^2 Which of the following must have a value of zero?
C
What do the +/- show in physics?
Direction
In general, Fnet equals
EF.
Until the middle of the 16th century, most people believed ____ was at the center of the universe?
Earth
A ball is dropped from a person's hand to Earth. Identify an action-reaction pair in this situation.
Earth exerts a force on the ball; the ball exerts a force on the Earth.
Two objects move separately after colliding, and both the total momentum and total kinetic energy remain constant. Identify the type of collision.
Elastic
Two billiard balls collide. Identify the type of collision.
Elastic.
What happens to an object in motion when it experiences a nonzero net external force?
Experiences an acceleration
When there is no air resistance, objects of different masses dropped from rest
Fall with equal accelerations and with equal displacements
The mass of an object determines how fast it will fall in free fall.
False
What term is used to describe the vector sum of all the forces acting on an object?
Net force
A ball is thrown up into the air. At what point in its trajectory will its acceleration equal zero?
Never
The amount of force equal to 1 kg * m/s^2 defines what SI unit?
Newton
Do action-reaction pairs result in equilibrium? Explain
No because they are on different objects. The object with greater mass has less inertia.
When a horse pulls on a cart, the car pulls on the horse with an equal but opposite force. How is the horse able to pull the cart?
Not reached equilibrium. Action and reaction pairs are acting on different obkects
How does the theory of field forces explain how objects could exert forces on each other without touching?
Objects exert forces when their fields interact
Which of the following equations is not an equation for power, P, in terms of work, W, displacement d, time interval, t, force, f, and/or velocity, v?
P = Fv / t
Two balls of dough collide and stick together. Identify the type of collision.
Perfectly inelastic
Two objects stick together and move with a common velocity after colliding. Identify the type of collision.
Perfectly inelastic
Which of the following is the motion of objects moving in two dimensions under the influence of gravity?
Projectile motion
In which of the following sentences is work used in the scientific sense of the word?
Sam and Rachel pushed hard, but they could do no work on the car.
In which of the following sentences is work used in the everyday sense of the word?
Sam and Rachel worked hard pushing the car.
Which of the following is a physical quantity that has a magnitude but no direction?
Scalar
Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree, wind velocity.
Scalar, scalar, vector (Duck, duck, goose!)
Identify the following quantities as scalar or vector: the speed of a snail, the time it takes to run a mile, the free-fall acceleration
Scalar, scalar, vector (Duck, duck, goose!)
The graph above describes the motion of a cyclist. During the interval shown, the cyclist is
Speeding up
How does the coefficient of static friction of two surfaces in contact compare to the coefficient of kinetic friction for the same two surfaces?
Static friction is greater
A piece of chalk is dropped by a teacher walking at a speed of 1.5 m/s. From the teacher's perspective, the chalk appears to fall
Straight down
What does the graph above illustrate about acceleration?
The acceleration varies.
In the graph above, how does the acceleration at A compare with the acceleration at B?
The accelerations at A and B are each zero.
When a car's velocity is positive and its acceleration is negative, what is happening to the car's motion?
The car slows down
When a car's velocity is negative and its acceleration is negative, what is happening to the car's motion?
The car speeds up.
A child with a mass of 23 kg rides a bike with a mass of 5.5 kg at a velocity of 4.5 m/s to the south. Compare the momentum of the child with the momentum of the bike.
The child has a greater momentum than the bike.
what are the units of the coefficient of friction?
The coefficient of friction has no units
Why does an astronaut weight less on the moon than on earth?
The gravitational field strength is less on the moon's surface than on Earth's surface
A hammer drives a nail into a piece of wood. Identify an action-reaction pair in this situation.
The hammer exerts a force on the nail; the nail exerts a force on the hammer.
A leaf falls from a tree and lands on the sidewalk. Identify an action-reaction pair in this situation.
The leaf exerts a force on the sidewalk; the sidewalk exerts a force on the leaf.
When comparing the momentum of two moving objects, which of the following is correct?
The less massive object will have less momentum if the velocities are the same.
The equation for the speed of an object in circular orbit is vt = root (G(m/r)). What does m represent in this equation?
The mass of the central object
If a nonzero net force is acting on an object, then the object is definitely
being accelerated
The written abbreviation ->(a), represents a quantity that has which of the following abbreviations in the text?
bold a
The equation for determining gravitational potential energy is PEg = mgh. Which factor(s) in this equation is (are) not intrinsic to an object?
both g and h
Which of the following equations can be used to directly calculate the change in an object's momentum?
change in p = F * change in t
Which of the following energy forms is not involved in hitting a tennis ball?
chemical potential energy