Concept Questions
A bicyclist starting at rest produces a constant angular acceleration of 1.30 rad/s2 for wheels that are 37.5 cm in radius.
(a) What is the bicycle's linear acceleration (in m/s2)? (Enter the magnitude.) Use: at=r(alpha) 0.4875 m/s2 (b) What is the angular speed of the wheels (in rad/s) when the bicyclist reaches 10.6 m/s? Use: Vt=rw --> w=Vt/r 28.27 rad/s (c) How many radians have the wheels turned through in that time? Use: theta=w^2/2alpha 307.38 rad (d) How far (in m) has the bicycle traveled? d=r(theta) 115.27 When rolling without slipping, a wheel's linear speed equals the tangential speed of a point on its rim and the linear distance it moves equals the arc length traced out by a point on its rim. m
You have a position vs time graph, position is in meters and time is in seconds. Two points on the best fit line of this graph are (1.0s, 5.2m) and (3.7s, 6.4m) calculate the slope of this graph, with units and correct sig figs
0.44m/s
The moment of inertia for a disk of radius r mass m rotating about its center axis is
1/2mr^2
How many masses were used in the centripetal force experiment?
2
If the angular acceleration were doubled for the same duration, by what factor would the angular displacement change?
2
An object of mass m is attached to a horizontal spring, stretched to a displacement A from equilibrium and released, undergoing harmonic oscillations on a frictionless surface with period T0. The experiment is then repeated with a mass of 4m. What's the new period of oscillation? T0/2 2T0 T0 T0/4
2To
The plunger of the ideal gas law apparatus is to be set to what initial volume
40mL
A block on the end of a spring is pulled to position x = A and released. Through what total distance does it travel in one full cycle of its motion? 2A 4A A/2 A
4A
If the satellite was placed in an orbit three times farther away, about how long would it take to orbit the Earth once? Answer in days, rounding to one significant figure.
5 days
The value of avogadro's number
6.02x10^23
A centripetal force is any force that induces a circular motion in an object. In our experiment what will serve as the centripetal force?
A combination of the force of gravity and the tension on the string
You are told to plot a graph position vs time
A position goes on the Y axis and time on the x axis
Three identical balls are thrown from the top of a building, all with the same initial speed. The first ball is thrown horizontally, the second at some angle above the horizontal, and the third at some angle below the horizontal, as in the figure below. Neglecting air resistance, rank the speeds of the balls and they reach the ground, from fastest to slowest.
All three balls strike the ground at the same speed.
If the net work done on a particle is zero, which of the following statements must be true?
Answer: The speed is unchanged. Wnet=change in KE= 1/2mv^2. KE is a scalar quantity, no direction specified. If you were to set the equation of Wnet=KEf-KEi as Wnet = 0, KEf and KEi would be equal to eachother. the work done on the particle is zero then according to work energy theorem change in kinetic energy also zero. Hence, it is found that initial and final kinetic energy are equal. If the initial and final kinetic energy are equal then the wrong options are the velocity is zero, velocity is unchanged. More information is needed and velocity is decreased. It is given that only the net work done on the particle is zero.if the velocity is unchanged the initial and final velocity will be same. This means that the particle is moving in the same direction with same speed.Here, force is not equal to zero because velocity have non-zero value, hence the displacement should be zero. To make the displacement zero the particle should be at the initial position at the end of the trip. Therefore, the direction of the particle can't be same. "Velocity is unchanged":we can find speed of the particle using work energy theorem "more information is needed":initial and final kinetic energy is equal. Velocity is a vector quantity and it is depending on the direction of motion. Hence the speed of the particle stays the same.
An object moves in a circular path with constant speed v. Which of the following statements is true concerning the object?
Both acceleration and velocity are changing
If the speed of a particle is doubled, what happens to its kinetic energy?
Change in kinetic energy is due entirely to the object's change in speed. In the formula for KE, speed in squared, so if you were to double the speed and then square it (2^2=4), kinetic energy is then quadrupled aka multiplied by four.
What property of a gas is not explicitly in the ideal gas law
Density
What is a real world application of an Atwood's Machine?
Elevators, bucket tied to a rope over a pulley, construction cranes
(cos(45))^2
Equals 1/2 or 0.5
The net force acting on the masses in this experiment in given by the equation
F= (M2-M1)g
In the Atwood machine experiment we will be using a instrument called the force sensor
False
A 78-kg base runner begins his slide into second base when he is moving at a speed of 3.4 m/s. The coefficient of friction between his clothes and Earth is 0.70. He slides so that his speed is zero just as he reaches the base.
For A, use W= the change in Kinetic energy (1/2mvf^2-1/2mvi^2) For B use Wnc=Fr x d... The answer you got from A set equal to (friction)(m)(g)(d), solve for d d= W/ (friction)(m)(g)
If the initial angle were smaller, with all the other quantities remaining the same, the kinetic energy of the grasshopper at its highest point would be:
Greater than before
A woman on a seesaw is at equilibrium. What happens if she leans back?
Her side of the board moves downward if she keeps legs and feet stationary but grasps the board with her hands to balance. It depends on whether she leans by moving her feet forward to balance.
If the student suddenly releases the weights, how does his own angular momentum, rotational kinetic energy, and angular speed change? (Select all that apply.) His rotational kinetic energy increases. His rotational angular speed decreases. His rotational kinetic energy decreases. His rotational kinetic energy remains the same. His angular momentum remains the same. His angular momentum increases. His rotational angular speed remains the same. His angular momentum decreases. His rotational angular speed increases
His angular momentum remains the same His rotational angular speed remains the same. His rotational kinetic energy remains the same.
The equation for impulse given in the lab manual is?
I=F*(change)t
If you repeated the rotational inertia lab with a larger hanging mass, should that change the values you would obtain for the moment of inertia of the ring and disk?
If hanging mass is changed, only the value of acceleration will change. There is no effect on the value of moment of inertia. the value would still be proximal to the same value we obtained.
If the slide were not frictionless, would the shape of the slide affect the final answer?
If the slide were not frictionless, a different shaped slide would result in different amounts of energy lost through friction. Therefore, the final answer would depend on the slide's shape.
In this lab we will make a velocity vs time graph of our collision. The max and min values of this graph will correspond to what physical quantities on this graph respectively?
Initial velocity and final velocity
Qualitatively, how will the diver's speed change if the diver takes a running dive off the end of the board?
It would increase
The Si unit for energy
Joule
Theory of Rotational inertia
Let us assume there is a mass m, initially at rest, that is attached to one end of a massless rod of length r, and the other end of the rod is attached to a frictionless pivot that is free to rotate 360o . If one were to apply a net force F to the mass it would induce rotational motion about the pivot point, but only the component of the applied for force that is tangential (at a right angle) to the length r would contribute to the change in motion of the mass. By Newton's Second Law we know the tangential force would be related to the tangential acceleration
Mark and David are loading identical cement blocks onto David's pickup truck. Mark lifts his block straight up from the ground to the truck, whereas David slides his block up a ramp on massless, frictionless rollers. Which statement is true?
Mark and David do the same amount of work
If you plot Net force vs Acceleration what physical quantity will the slope of that graph represent.
Mass
In the conversion of mechanical energy experiment what piece of equipment didn't we use?
Micrometer
For an object moving in a circle, even if the speed is constant, there must be a non-zero net force action on it to get it to change it's direction of motion, and that means its state of motion is changing. Which of Newtons laws tells us that if an objects state of motion is changing then there must be a non-zero net force acting on it?
Newton's first law
Is the frequency of a wave affected by the wave's amplitude? Yes. Increasing amplitude increases frequency. Yes. Increasing amplitude decreases frequency. No. They are independent of each other.
No they are independent of each other
In exercise 3 of the graph analysis of data, equation 4 describes the behavior of a simple pendulum. What does T in equation 4 represent?
Period
For a floating object how does its density relate to the density of the fluid?
Pfluid>Pobject
A pendulum clock depends on the period of a pendulum to keep correct time. Suppose a pendulum clock is keeping correct time and then Dennis the Menace slides the bob of the pendulum downward on the oscillating rod. Does the clock run slow, fast, or correctly? slow correctly fast
Slow
Does a simple pendulum of length 0.50 m have a larger or smaller frequency of vibration than a simple pendulum of length 1.0 m? Explain. (Select all that apply.)
Smaller. A longer pendulum has a longer period and smaller frequency according to ω = mg/(mL) = g/L Smaller. A longer string makes the restoring force smaller for each pendulum angle.
In this experiment in order to determine the max height of the projectile, compared to its initial position, you will have to do this calculation...
Subtract the height of the mini launcher to measure height to calculate max height.
Suppose the radius of the wheel is doubled. Are the answers affected? If so, in what way? (Select all that apply.)
The angle rotated through from t = 0 to t = 2.00 s is the same. The angular speed at t = 2.00 s is the same.
The calculated change in momentum (change in p) is negative while the impulse given by the area under the curve (I area) is positive. Why is that?
The area under the curve is positive because it is gaining momentum and it gains momentum until it makes contact and loses momentum as well as change direction
A bowling ball is suspended from the ceiling of a lecture hall by a strong cord. The ball is drawn away from its equilibrium position and released from rest at the tip of the demonstrator's nose, as shown in the figure below.
The ball does not strike her on its return swing because, in the beginning, the ball has gravitational potential energy and no kinetic energy. The ball will increase in kinetic energy and lose potential energy as the ball swings. Because of the law of conservation of energy and we neglect any kind of nonconservative force, KE must equal PE thus the ball will return to the girl without KE and will not strike her but return almost to its original position and seeming to stop there with PE.
Theory of Ideal Gas
The behavior of a gas depends on a number of variables, namely; pressure P, volume V, temperature T, and the amount of gas n. These variables are related to each other by an equation of state called The Ideal Gas Law.
When an object is being submerged into a fluid the buoyant force acting on it does what?
The buoyant force does not change
When four people with a combined mass of 310 kg sit down in a 2000-kg car, they find that their weight compresses the springs an additional 0.90 cm. (a) what is the effective force constant of the springs? in N/m (b) The four people get out of the car and bounce it up and down. What is the frequency of the car's vibration?
The expression for Newton's second law for the case of spring in the car is as follows: F=mpa Here, the mass of passengers is mp Replace F with kx and a with g -kx = mpg Neglect the negative sign. Rearrange the above expression for the spring constant. k=mpg/x This will give you the spring constant k Note that this new displacement on the position of the spring only happened when the people got in and therefore is only dependent on their weight and we do not need to include the car's mass The frequency of the vibration of spring depends on the mass of the car but not on the mass of passengers traveling in it. Therefore use the formula f=1/2pi(*square root of* k/m) using only the mass of the car.
How is the centripetal force related to the radius of the circular path the mass is moving on?
The force is inversely proportional to the radius of the path
How is the centripetal force related to the tangential velocity of the mass?
The force is proportional to the square of the tangential velocity of the mass
How then would a smaller initial angle change the initial kinetic energy, and the initial speed, that the grasshopper needs to reach the same height of 1 meter?
The grasshopper must jump faster and therefor with more kinetic energy
In this lab we will make a force vs time graph of our collision. What will the area between the horizontal axis and the curve of our graph physically represent?
The impulse of impact
A planet has two moons with identical mass. Moon 1 is in a circular orbit of radius r. Moon 2 is in a circular orbit of radius 2r. The magnitude of the gravitational force exerted by the planet on Moon 2 is which of the following compared with the gravitational force exerted by the planet on Moon 1?
The magnitude of the gravitational force exerted by the planet on moon 2 will be one fourth of the gravitational force exerted by the planet on moon 1
When recording a manual measurement....
The number of digits to be recorded depends on the instrument being used and the last digit in the number recorded will be a guess
Given your standard kinematic equation v=at+vi, and the standard equation for a line y=mx+b, when asked to graph velocity vs time graphically vi would correspond to?
The y axis intercept
Bob, of mass m, drops from a tree limb at the same time that Esther, also of mass m, begins her descent down a frictionless slide. If they both start at the same height above the ground, which of the following is true about their kinetic energies as they reach the ground?
They have the same kinetic energy
The impulse a single object experiences during a collision is related to it's change in momentum how?
They have the same value, because they are the same thing
In this experiment (atwood machine), we made the assumption that the tension and the acceleration experienced by the two subsystems (the two pulleys) were exactly the same. Why are these good and/or valid assumptions?
This allows us to better focus on what we are trying to measure
Any liquid or gas can be considered a fluid
True
Assuming the same mass and similar radius, the moment of inertia of a ring is larger than a disk
True
The torque induced by an applied force F among other things, depends on the straight line distance from the point the force is being applied on the mass to point the mass is rotating about.
True
When collecting data for this experiment we must set the Temperature to Kelvins.(Ideal gas law)
True
The total change of momentum for a closed system is?
Zero
The graph of acceleration vs time more or less will be
a horizontal line with no slope
What are the two defining characteristics of a soft collision are
a small force and large time span
Mars rotates on its axis once every 1.02 days (almost the same as Earth does). (a) Find the distance from Mars at which a satellite would remain in one spot over the Martian surface. (Use 6.42 1023 kg for the mass of Mars.)
a) 20300000 (b) Find the speed of the satellite. 1450
For the Constant Total Mass data (Table 1), plot a graph of Fnet vs. aexp, and find the best fit line for the data. (a) What are the units of the slope? (3 points) (b) What physical quantity does the slope of the best-fit line represent?
a) N/m?s^2 b)Joule.....
Objects moving along a circular path have a centripetal acceleration provided by a net force directed toward the center. Identify the force(s) providing the centripetal acceleration in each of these cases: a planet in circular orbit around its sun; a car going around an unbanked, circular turn; a rock tied to a string and swung in a vertical circle, as it passes through its highest point; and a dry sock in a clothes dryer as it spins in a horizontal circle. (Select all that apply.) a) a planet in circular orbit around its sun b)a car going around an unbanked, circular turn c)a rock tied to a string and swung in a vertical circle, as it passes through its highest point d)and a dry sock in a clothes dryer as it spins in a horizontal circle
a) gravity b) friction c)Tension and Gravity d) normal force
The equation that gives the theoretical value of acceleration in the atwood machine lab
a=F(M2-M1)
You are asked to plot velocity vs time graph, the slope of this graph will represent what physical quantity
acceleration
Explain how the force vs acceleration plot relates to newtons second law
acceleration a mass experiences is proportional to the net force applied to it and inversely proportional to its inertial mass a=fnet/m, when there is no net force, acceleration is zero and velocity is constant.
What specific physical quantity does the slope of the two middle points from the position vs time graph represent?
average velocity
Is the frequency of vibration of a heavy vehicle greater or smaller than that of a lighter vehicle, assuming the two vehicles are supported by the same set of springs? Explain. (Select all that apply.) OThe heavier vehicle has the lower frequency. Greater weight implies greater mass, less rapid acceleration by the spring, and slower vibration. OThe heavier vehicle has the higher frequency of vibration, because its mass is larger. OThe heavier vehicle has the higher frequency according to the expression for frequency f in terms of k and mass m. OThe heavier vehicle has the lower frequency according to the expression for frequency f in terms of k and mass m. OThe heavier vehicle has the higher frequency of vibration because gravity pulls it back toward Earth more strongly on each bounce.
both vehicles use the same springs so k is the same for each the heavier one has a larger mass m so the first choice is true The heavier vehicle has the lower frequency. Greater weight implies greater mass, less rapid acceleration by the spring, and slower vibration. the second choice is false because frequency has an inverse dependency on mass the third choice also is false because frequency has an inverse dependency on mass the fourth choice is true The heavier vehicle has the lower frequency according to the expression for frequency f in terms of k and mass m. the fifth choice is false because gravity doesn't play a role
Archimedes principle says that in case of an object completely submerged in a fluid, solely due to its own weight the buoyant force is
equal to the weight of the fluid displaced
Archimedes principle does not apply to partially submerged objects
false
The period of a simple pendulum is measured to be T on Earth. If the same pendulum were set in motion on the Moon, its period would be which of the following? greater than T less than T equal to T
greater than T
If the mass is doubled, is the magnitude of the acceleration of the system at any position doubled, halved, or unchanged? doubled halved unchanged
halved
If the static friction coefficient were increased, the maximum safe speed would:
increase
The magnitude of the acceleration the masses experience in the Atwood machine
is less than g
The 'time of flight' of a projectile, initially fired perfectly horizontal is dependent upon
its initial height
The SI units for mass, length, and time are
kilograms, meters, and seconds
The purpose of the lab measures experiment is to
learn the proper use of the basic laboratory measuring devices and to perform basic lab calculations
In position velocity acceleration lab the track that the cart will be moving should be
lying flat on the table
Position vs time graph
m/s displacement and distance traveled by cart
Velocity vs time graph
m/s^2 magnitude of cart and direction in which it traveled in a period of time
Acceleration vs time graph
m/s^3 Shows the acceleration of the cart is constant in the experiment
The measuring devices used in the measurements lab
metric ruler, micrometer, vernier caliper, lab balance
If the mass of the grasshopper is m, and its maximum height h, with q the initial angle, the change in kinetic energy of the grasshopper between the start of its jump and its greatest height has magnitude:
mgh or potential energy is independent of the initial angle
we derived an equation for the acceleration: 𝑎 =𝑔(𝑚2−𝑚1)/(𝑚2+𝑚1) . Briefly explain what the numerator and denominator are in a physical sense
numerator is the ratio given by the differences of the two masses that describe the magnitude of the acceleration that the masses experience, the denominator is the sum to give the net force which is equal to the gravitational acceleration multiplied by the difference of the two masses
If the amplitude of a system moving in simple harmonic motion is doubled, which of the following quantities doesn't change? period maximum speed maximum acceleration total energy
period
A wave in one medium encounters a new medium and enters it. Which of the following wave properties will be affected in this process? (Select all that apply.) frequency speed wavelength
speed and wave length
The net torque a mass experiences is given by
t=a*I
When a mass is being uniformly accelerated, that means
the mass is moving with constant acceleration
What happens if the woman suddenly slides closer to the hub by 0.400 m? (Select all that apply.) Here the woman is applying force to the left side of the door (if unhindered the rotation continues clockwise (-)) Situation: Revolving door and discussion is about the torques of either person exerting a specific amount of force at a particular distance away from the axis of rotation.
the new net torque is in the opposite direction and the new net torque has a greater magnitude
apparent weight is...
the weight with forces acting on the object
What is not an assumption about an ideal gas
there is an extremely large number of them
The law of conservation of mechanical energy says that in the absence of non-conservative forces, such as friction the total mechanical energy possessed by a system is conserved
true
Andrea and Chuck are riding on a merry-go-round. Andrea rides on a horse at the outer rim of the circular platform, twice as far from the center of the circular platform as Chuck, who rides on an inner horse. When the merry-go-round is rotating at a constant angular speed, Andrea's tangential speed is which of the following?
twice of chuck's
what equation will describe the velocity vs time graph
v=vi+at
During the moment of inertia lab
we measured the moment of inertia of a disk and ring
