Final Review- Lecture Multiple Choice and Show Work

E. -40 degrees

At what temperature do Celsius and Fahrenheit scale have the same value?

b) ... -1.5, -0.5, 0.5, 1.5, 2.5, ...

At what times (t=?) will the object pass through equilibrium?

C

Bob the block is placed next to the cylindrical glass wall of an amusement park ride. The cylinder then begins spinning with a constant angular velocity, and spinning Bob remains stuck to the wall even when the floor drops away. The free-body diagram of all forces acting on Bob looks like:

3. 2/3

By what factor does the absolute gas pressure change if the volume is tripled and the temperature is doubled?

a) A = B = C

How does the pressure of the water on the bottom of the container compare?

1. A

Identical constant forces F push identical Blocks A and B from the start line to the finish line. Block A is initially at rest, but block B is initially moving to the right. Which block incurs the greater change in momentum while moving from the start to the finish line?

1. A

Identical constant forces F push identical Blocks A and B from the start line to the finish line. Both blocks start at rest, but block A has 4 times as much mass as block B. Which block incurs the greater change in momentum while moving from the start to the finish line?

5. Cool it

In the experimental arrangement shown, can you decrease the pressure without changing the volume? If so, how?

3. Remove some mass on top of the piston

In the experimental arrangement shown, how would you decrease the pressure without changing the temperature?

5. Cool it

In the experimental arrangement shown, how would you decrease the volume without changing the pressure?

2. Add more mass on top of the piston

In the experimental arrangement shown, how would you decrease the volume without changing the temperature?

1) A > B > C

Rank the plots according to the corresponding frequency of the oscillator.

3. Both have the same C.O.M. speed

Strings are wound around two identical pucks: one is around its outer rim; the other is around its axle. You pull both pucks from rest by using the same force F. Both pucks start to move on a frictionless surface. 5 seconds later, which puck has greater center-of-mass speed?

1. Puck 1

Strings are wound around two identical pucks: one is around its outer rim; the other is around its axle. You pull both pucks from rest by using the same force F. Both pucks start to move on a frictionless surface. 5 seconds later, which puck has greater rotational kinetic energy?

1. Puck 1

Strings are wound around two identical pucks: one is around its outer rim; the other is around its axle. You pull both pucks from rest by using the same force F. Both pucks start to move on a frictionless surface. 5 seconds later, which puck has greater total kinetic energy? ( Do you know why?)

3. Both arrive at the same time

Strings are wound around two identical pucks: one is around its outer rim; the other is around its axle. You pull both pucks from rest by using the same force F. Both pucks start to move on a frictionless surface. Which puck arrives at the finish line first?

1. Yes, and it moves to the right.

Suppose you are on a cart initially at rest that rides on a frictionless track. If you throw a ball off the cart towards the left, will the cart be put into motion?

3. Will not change.

Suppose you are on a cart that is moving at a constant speed v toward the left on a frictionless track. If you throw a massive ball straight up (from your perspective), how will the speed of the cart change?

2. Yes, and it moves to the left.

Suppose you are on a cart which is initially at rest that rides on a frictionless track. You throw a ball at a vertical surface that is firmly attached to the cart. If the ball bounces straight back as shown in the picture, will the cart be put into motion after the ball bounces back from the surface?

8.3 m and no, his mass is independent

Ted decides to ride the rump roaster. He starts at the top of a 5 meter high frictionless slide. At the bottom he enters a sliding zone that has a coefficient of friction 0.6 with his bottom. What is the minimum length L of the zone that will stop him, and does the length depend on Ted's mass?

1. decreases

The angular speed of a freely rotating disk around its center is w (omega). You drop a heavy block onto the disk along the direction as depicted below, and the block then stays on the disk. The angular speed of the disk-block system now:

Velocity zero, force towards -x

This is the position vs. time graph of a mass on a spring. What can you say about the velocity and the net force at the instant indicated by the dotted line?

6. They are ALL EQUAL

Three balls of equal mass are fired simultaneously with equal speeds from the same height h above the ground. Ball 1 is fired straight up, ball 2 is fired straight down, and ball 3 is fired horizontally. Rank in order from largest to smallest their speeds v1, v2, and v3 an instant before they hit the ground. (Neglect friction.) Ball 1

3. (0 m, 0.58 m)

Three tiny equal-mass magnets are placed on a horizontal frictionless surface at the corners of an equilateral triangle (all sides 2 m and all angles 60 0). When the magnets are released, they attract and quickly slide to a single point. What are the x and y coordinates of that point? (Before release, the y-axis passed through the top ball and the x-axis passed through the bottom balls.)

5. 60 degrees

Two 1 kg wheels with fixed hubs start from rest and equal- magnitude 1 N forces are applied to each. The hub and spokes are virtually massless. In order to impart identical angular accelerations, at what angle (theta) must be applied with respect to horizontal?

4. 2 N

Two 1 kg wheels with fixed hubs start from rest, and forces are applied as shown. Assume that the hub and spokes are massless, and that F(1) = 1 N. In order to impart identical angular accelerations, how large must F(2) be?

3. Twice

Two balls, one twice as massive as the other, are dropped from the roof of a building (free fall). Just before hitting the ground, the more massive ball has ______ the kinetic energy of the less massive ball. (Neglect air friction.)

6. 20 m/s

Two cars initially at rest on a frictionless surface are blown apart by an explosion. The one with twice the mass ends up moving to the right at 10 meters/second. The less massive car ends up moving to the left at what speed?

1. 1

Two cylinders with the same radius and mass start from rest and roll down (without slipping) two hills from the same height. Cylinder 2 has a massless axle with a smaller radius. There is a groove in the hill so that only the axle touches. Which object reaches the bottom first?

1. A

Two equal-mass balls swing down and hit identical bricks while traveling at identical speeds. Ball A bounces back, but ball B just stops when it hits the brick. Which ball has a better chance of knocking the brick over?

1atm = 1.013 x 10^5 Pa

What is 1 atm in Pa (Pascals)?

1 cm^3 = 1 x 10^-6 m^3 OR 0.000001 m^3

What is 1 cm^3 in m^3?

B) >0 from A to O

What is the acceleration at point A?

b) 2cm

What is the amplitude of of the motion?

e) π rad/s

What is the angular frequency of the motion?

4) 2 rad/s

What is the angular frequency of this harmonic oscillator?

b) 1/2 Hz

What is the frequency of the motion?

F = m(v^2/r) because centripetal acceleration = v^2/r

What is the net inward force of an object rotating with centripetal acceleration?

d) 2s

What is the period of the motion?

B. 12.5%

What is the thermal efficiency of this heat engine?

4) +π/2

What is the value of ø with zero velocity and at its maximum negative amplitude x?

1) 0

What is the value of ø with zero velocity and at its maximum positive amplitude x?

g) None of the above (net force = 0)

Which arrow points in the direction of the net force on the block?

A. Engine 1

Which engine has the larger thermal efficiency?

6) All of the above

Which of the following demonstrates simple harmonic motion?

5. ΔU < 0, W = 0, Q < 0

Which of the following statement is true about the ideal gas process A to D?

4. ΔU = 0, W < 0, Q > 0

Which of the following statement is true about the ideal gas process D to B?

4. ΔU = 0, W < 0, Q > 0

Which of the following statement is true about the ideal- gas isothermal process from A to B?

4) d

Which one has the phase constant π/4?

3. 1 rad/s^2

You are given the same small wheel and force as in the previous problem. As before, the spokes and hub are virtually massless. What is the magnitude of the wheel's angular acceleration?

2. Constant volume

You need to raise the temperature of a gas by 10 °C. To use the least amount of heat energy, should you heat the gas at constant pressure or at constant volume?

Downward, constant magnitude

You throw a ball vertically upward. While the ball is still moving up, which statement best describes the direction and magnitude of the ball's acceleration?

Upward, decreasing magnitude

You throw a ball vertically upward. While the ball is still moving up, which statement best describes the direction and magnitude of the ball's velocity?

3. 4pi /s

A disk that initially spins at 2 revolutions/sec is braked uniformly to a stop in ½ second. What is its initial angular speed w?

3. -8pi /s^2

A disk that initially spins at 2 revolutions/sec is braked uniformly to a stop in ½ second. What is the value of angular acceleration a? (Negative a means stopping)

4. 497 m/s

A 20 gram bullet with an initial velocity v is shot into a 5 kg wood block attached to a pivot with massless strings. After the collision, the block swings upward to a maximum height h = 0.2m above its initial position. What was the initial velocity of the bullet?

45m

A ball is launched vertically upward from ground level with an initial velocity of 30 m/s. what maximum altitude does it reach above the ground? Use |g|=10 m/s2.

Velocity

A ball is thrown vertically upward at position y=0. Assume that the vertical coordinate y increases in the downward direction. At its maximum height, which of the following quantities starts to change sign?

1. h

A block is launched up a frictionless 40 slope with an initial speed v and reaches a maximum vertical height h. The same block is launched up a frictionless 20 slope with the same initial speed v. On this slope, the block reaches a maximum vertical height of _____

2. Upward net force and zero velocity

A block is oscillating up and down. When the block reaches its lowest point, what's the velocity and force on the block?

1. h (Velocity is independent of mass in this case)

A block of mass m is at rest at the top of a ramp of vertical height h. The block starts to slide down the frictionless ramp and reaches a speed v at the bottom. If a block of mass 2m were to reach the same speed v at the bottom, it would need to slide down the ramp at the height of _____.

5. 4h

A block of mass m is at rest at the top of a ramp of vertical height h. The block starts to slide down the frictionless ramp and reaches a speed v at the bottom. If the same block were to reach a speed 2v at the bottom, it would need to slide down a frictionless ramp of vertical height _____.

D

A block sits at rest and stays at rest on a motionless slide with frictional surfaces. Which of the following sketches most closely resembles the correct freebody diagram for all forces acting on the block? Each red arrow represents a force. Observe their number and direction, but ignore their lengths.

3) N<w

A car is rolling over the top of a hill at speed v. At this instant when the car is moving at the top...

2. Yes

A car rounds a circle while maintaining a constant speed. At the instant shown below, is there an acceleration on the car as it rounds the curve?

3) the net force is the radius of rotation in the direction from the outside to the inside.

A car rounds a circle while maintaining a constant speed. Which arrow represents the direction of the net force on the car as it rounds the curve at the instant shown in the figure?

2. W = -f*d

A car traveling to the right with a speed v brakes to a stop in a distance d. What is the work done on the car by the frictional force f? (Assume that the frictional force is constant).

3. -3.3 m/s

A car with a mass M is moving toward another car with a mass 2 M on a frictionless surface. Both cars have a speed of 10 m/s. Subsequently, they collide and stick together. What is the final velocity of the two car system?

At 10 m/s = 7460 N At 30 m/s = 2486.67 N

A car's engine provides a constant output power of 100 horsepower (74,600 W). What is its pushing force at 10 m/s? At 30 m/s?

1. They are ALL EQUAL

A child starting from rest slides down each of the four frictionless slides A to D. Each has the same vertical height. Rank in order, from largest to smallest, her speeds V (of A) to V (of D) at the bottom.

2. 0.5 revolution

A disk that initially spins at 2 revolutions/sec is braked uniformly to a stop in ½ second. A bug is stuck on the outer edge 1 meter from the center. How many revolutions does the bug go during the time it takes the disk to stop?

4pi /s 12.6 m/s 8pi /s 25.1 m/s

A disk that initially spins at 2 revolutions/sec is braked uniformly to a stop in ½ second. A bug is stuck on the outer edge 1 meter from the center. What is the initial angular speed? Initial tangential speed? Angular acceleration? Tangential aceleration?

3. -1 m

A large skinny guy with mass 2M and a smaller guy with mass M are holding onto a massless pole while standing on frictionless ice, as shown below. If the big guy pulls himself toward the little guy, where would they meet?

3. -1 m

A large skinny guy with mass 2M and a smaller guy with mass M are holding onto a massless pole while standing on frictionless ice, as shown below. If the little guy pulls himself toward the big guy, where would they meet?

3. They have the SAME final kinetic energy

A lighter car and a heavier truck, each initially at rest, have the same constant netforce F applied on them. After both vehicles travel a distance d, which of the following statements is true? (Ignore friction)

1. The work done on both vehicles is the SAME

A lighter car and a heavier truck, each traveling to the right with the same speed v, hit the brakes. The retarding frictional force F on both cars turns out to be the same constant. After both vehicles travel a distance d (and both are still moving), which of the following statements is true?

2(pi)rdr

A mass M is uniformly distributed over a disk radius R and area piR^2. The area of a thin ring inside the disk with radius r and thickness dr is:

4. (2M/R^2)rdr

A mass M is uniformly distributed over a disk radius R. The mass contained in a thin ring with radius r and thickness dr inside the disk is given by: (Remember to use a ratio of the ring area to the total area of the disk.)

Mr^2

A mass M is uniformly distributed over the circumference of a thin ring with radius r. The moment of inertia for this ring when rotating about its center is:

2. x^2(M/L)dx

A mass M is uniformly distributed over the length L of a thin rod. The contribution to the moment of inertia by a short element dr is given by:

2. (M/L)dx

A mass M is uniformly distributed over the length L of a thin rod. The mass inside a short element dx is given by:

0.8m, 0.4s

A person throws a ball upward with an initial velocity of 4 m/s; take g=10 m/s2. What is the maximum height that the ball will reach and what is the time that the ball will take to reach that maximum height?

2. W = 0

A satellite travels with a constant speed |v| as it moves around a circle centered on the earth. How much work is done by the gravitational force F on the satellite after it travels half way around the earth in time t?

- 0.2 m/s

A small block of 1.0 kg is set on a irregular ramp at an initial height of h. The ramp has a mass of 10.0 kg and can move freely without friction on the ground. Both the ramp and the block are at rest initially. After the block is released, it glides down the ramp and moving the right on the ground with a speed of 2 m/s. What is the velocity of the ramp? (There are no frictions on all surfaces.)

Velocity of ramp = 0.2 m/s

A small block of 1.0 kg is set on an irregular ramp at an initial height of h. The ramp has a mass of 10.0 kg and can move freely without friction on the ground. Both the ramp and the block are at rest initially. After the block is released, it glides down the ramp and is moving to the right on the ground with a speed of 2 m/s. What is the velocity of the ramp? (There are no frictions on all surfaces.)

y = R/2

A small object of mass m starts from rest at the position shown and slides along the frictionless loop-the-loop track of radius R. What is the smallest value of y such that the object will slide without losing contact with the track?

2. 8 m/s

A spring-loaded gun shoots a plastic ball with a speed of 4 m/s. If the spring is compressed twice as far, the ball's speed will be

5. 6m

A spring-loaded toy dart gun shoots a dart to a maximum height of 24 meters. The same dart is again shot upward, but this time the spring is compressed only half as far before firing. Neglecting friction and assuming an ideal spring, how far up does the dart go this time? Assume that the compression of the spring is negligible compared to the travel of the dart.

D. It must be +8J/K or more

A thermodynamic process occurs in which the entropy of a system changes by −8 J/K. According to the second law of thermodynamics, what can you conclude about the entropy change of the environment?

90 J

A uniform disk, with mass M = 2.5 kg and radius R = 20 cm, mounted on a fixed horizontal axle. A block with mass m = 1.2 kg hangs from a massless cord that is wrapped around the rim of the disk. If block m falls 15 m from rest, what is the rotational kinetic energy of the pulley?

θmin = tan^(-1)(1/(2*static coefficient))

A uniform ladder of length L, rests against a smooth, vertical wall The mass of the ladder is m, and the coefficient of static friction between the ladder and the ground is μs= 0.40. Find the minimum angle θmin at which the ladder does not slip.

A

Driving a car at 60 MPH, Mary tests her brake by uniformly coming to a complete stop in 4 seconds. Then she resumes speed, taking 8 seconds to return to 60 MPH. Which of the following graphs best represents her velocity?

A

Driving a car at 60 MPH, Mary tests her brake by coming to a complete stop in 4 seconds. Then she resumes speed, taking 8 seconds to return to 60 MPH. A motion diagram is created by illuminating her car with a strobe at 2 second intervals. Which of the following best represents the correct diagram? Mary's car is represented by a dot.

1. P(b) > P(a) = P(c) > P(d)

Four students run up the stairs in the time shown. Rank in order, from largest to smallest, their power outputs P(a) to P(d).

2. 71 m/s

The engine of a 1000 kg sports car rotates the tires, creating a net forward pushing force F on the tires of the car that varies as a function of distance. The force is shown below. If the car starts at rest, what is the speed of the car after traveling 500 meters?

2. < L (the final magnitude L is less than the initial L)

The magnitude of the angular momentum for a freely rotating disk around its center is L. You drop a heavy block onto the disk along the direction as depicted below, and the block then stays on the disk. Now the magnitude of the angular momentum for the disk-block system is:

3. = L (the angular momentum stays the same)

The magnitude of the angular momentum for a freely rotating disk around its center is L. You drop a heavy block onto the disk along the direction as depicted below, and the block then stays on the disk. Now the magnitude of the angular momentum for the disk-block system is:

2 m/s

The spring is relaxed at x0. The block is pushed against the spring to x1 and held stationary (the spring is compressed.) Then the block is released. What is the block's velocity at x2?