Question 1

Is it possible for an object moving at a constant speed around a circular path to be subject to an acceleration?

Accepted Answer

A)  No: The path would not be a circle. 
B)  No: An object can have only one or the other at any given time. 
C)  Yes, this is possible. 
D)  More information is needed to work out the answer. 
A)  No: The path would not be a circle. 
B)  No: An object can have only one or the other at any given time. 
C)  Yes, this is possible. 
D)  More information is needed to work out the answer. C

Question 2

The velocity of an object with respect to reference frame A is equal to

Accepted Answer

A)  the velocity of the object with respect to reference frame B added vectorially to the velocity of reference frame A with respect to reference frame B. 
B)  the velocity of the object with respect to reference frame B added vectorially to the velocity of reference frame B with respect to reference frame A. 
C)  Both of the first two responses are correct. 
D)  Neither of the first two responses is correct. 
A)  the velocity of the object with respect to reference frame B added vectorially to the velocity of reference frame A with respect to reference frame B. 
B)  the velocity of the object with respect to reference frame B added vectorially to the velocity of reference frame B with respect to reference frame A. 
C)  Both of the first two responses are correct. 
D)  Neither of the first two responses is correct. B

Question 3

A boat travels at a constant speed with respect to still water. Now suppose the water is moving with respect to the bank at a speed almost as large as the speed of the boat with respect to still water. Compare the time taken for a round trip of constant distance (with respect to the bank) in the boat under two scenarios: downstream, then upstream or cross-stream, then back. The "down-up" time is

Accepted Answer

A)  larger than the "across-back" time. 
B)  equal to the "across-back" time. 
C)  less than the "across-back" time. 
A)  larger than the "across-back" time. 
B)  equal to the "across-back" time. 
C)  less than the "across-back" time. A

Question 4

A baseball is hit by a bat and is launched in a projectile motion at 30o above the horizontal. At the top of the baseball's trajectory

Accepted Answer

A)  its acceleration is zero and its velocity is nonzero. 
B)  both its acceleration and its velocity are zero. 
C)  its acceleration is nonzero and its velocity is zero. 
D)  its acceleration is nonzero and its velocity is nonzero. 
A)  its acceleration is zero and its velocity is nonzero. 
B)  both its acceleration and its velocity are zero. 
C)  its acceleration is nonzero and its velocity is zero. 
D)  its acceleration is nonzero and its velocity is nonzero.

Question 5

A toy car moving along the x axis at 3.0 m/s is accelerated uniformly for 4.0 s at 0.40 m/s2 along the y axis. The toy car's speed at the end of the 4.0 s is:

Accepted Answer

A)  1.0 m/s. 
B)  1.4 m/s. 
C)  3.0 m/s. 
D)  3.4 m/s. 
E)  4.6 m/s. 
A)  1.0 m/s. 
B)  1.4 m/s. 
C)  3.0 m/s. 
D)  3.4 m/s. 
E)  4.6 m/s.

Question 6

A student driving her car at a constant speed makes a left turn. Her bag, on the passenger seat, slides and hits the passenger door. Which statement is correct?

Accepted Answer

A)  The bag was pushed toward the door because it experienced a centripetal acceleration. 
B)  The bag was not pushed toward the door. It just tried to maintain its motion at constant speed in a straight line. 
C)  The bag was pushed toward the door because it was too heavy. 
D)  None of these explanations is true. 
A)  The bag was pushed toward the door because it experienced a centripetal acceleration. 
B)  The bag was not pushed toward the door. It just tried to maintain its motion at constant speed in a straight line. 
C)  The bag was pushed toward the door because it was too heavy. 
D)  None of these explanations is true.

Question 7

A basketball is shot from a free-throw range. At the top of the basketball's trajectory, its acceleration is

Accepted Answer

A)  zero. 
B)  equal to the acceleration due to gravity. 
C)  less than the acceleration due to gravity. 
D)  more than the acceleration due to gravity. 
E)  unknown; more information is needed to work out the answer. 
A)  zero. 
B)  equal to the acceleration due to gravity. 
C)  less than the acceleration due to gravity. 
D)  more than the acceleration due to gravity. 
E)  unknown; more information is needed to work out the answer.

Question 8

A child is riding on a Ferris wheel that is rotating clockwise at a constant speed. When the child is at the top of the wheel, her acceleration

Accepted Answer

A)  points vertically downward. 
B)  points vertically upward. 
C)  points horizontally toward the right. 
D)  has a downward vertical component and a horizontal component pointing right. 
E)  has a downward vertical component and a horizontal component pointing left. 
A)  points vertically downward. 
B)  points vertically upward. 
C)  points horizontally toward the right. 
D)  has a downward vertical component and a horizontal component pointing right. 
E)  has a downward vertical component and a horizontal component pointing left.

Question 9

A train is traveling east at 30 km/h. After it rounds a curve, it travels south at 40 km/h. The magnitude of its average acceleration is

Accepted Answer

A)  10 km/h. 
B)  35 km/h. 
C)  50 km/h. 
D)  70 km/h. 
A)  10 km/h. 
B)  35 km/h. 
C)  50 km/h. 
D)  70 km/h.

Question 10

A car travels one lap around a circular track in 120 s. The diameter of the track is 30 m. The car's average speed is

Accepted Answer

A)  0.0 m/s. 
B)  0.13 m/s. 
C)  0.25 m/s. 
D)  1.6 m/s. 
A)  0.0 m/s. 
B)  0.13 m/s. 
C)  0.25 m/s. 
D)  1.6 m/s.

Question 11

An object is undergoing uniform circular motion. Its speed is 10 m/s and the radius of its path is 15 m. When its speed is halved, its centripetal acceleration is

Accepted Answer

A)  four times larger than the original centripetal acceleration. 
B)  twice as large as the original centripetal acceleration. 
C)  the same as the original centripetal acceleration. 
D)  half of the original centripetal acceleration. 
E)  a fourth of the original centripetal acceleration. 
A)  four times larger than the original centripetal acceleration. 
B)  twice as large as the original centripetal acceleration. 
C)  the same as the original centripetal acceleration. 
D)  half of the original centripetal acceleration. 
E)  a fourth of the original centripetal acceleration.

Question 12

A yellow ball rolling rapidly along a tabletop rolls off the edge and falls to the floor. At the same instant, a blue ball having the same mass and shape as the yellow one is dropped from the same height. The ball that has the larger vertical velocity component when it hits the floor is

Accepted Answer

A)  the yellow ball. 
B)  the blue ball. 
C)  neither; both have the same vertical velocity component. 
D)  unknown; one needs to know the speed of the yellow ball just before it rolls off the edge to work out the answer. 
A)  the yellow ball. 
B)  the blue ball. 
C)  neither; both have the same vertical velocity component. 
D)  unknown; one needs to know the speed of the yellow ball just before it rolls off the edge to work out the answer.

Question 13

For the two-dimensional motion of a projectile launched from the ground, all of the following apply except

Accepted Answer

A)  the total travel distance of the projectile in the air is greater than the straight paths connecting the launch point, the maximum height point, and the final impact point. 
B)  the vertical component of velocity is never greater than at the instant of launching. 
C)  the minimum speed occurs at the midpoint in time of the flight. 
D)  the time of flight to half the maximum height is greater than 1/4 the total time of flight. 
A)  the total travel distance of the projectile in the air is greater than the straight paths connecting the launch point, the maximum height point, and the final impact point. 
B)  the vertical component of velocity is never greater than at the instant of launching. 
C)  the minimum speed occurs at the midpoint in time of the flight. 
D)  the time of flight to half the maximum height is greater than 1/4 the total time of flight.

Question 14

A roller coaster car travels at a constant speed on a track that forms a circular loop in a vertical plane. The car's acceleration is

Accepted Answer

A)  zero. 
B)  nonzero. 
A)  zero. 
B)  nonzero.

Question 15

A ball is connected by two massless strings to a vertical, rotating rod, and it moves in a horizontal circle. The strings are tied to the rod, are taut, and form two sides of an equilateral triangle. A photograph of the system is taken at moment t and is shown in the figure here. At t the centripetal acceleration of the ball is

Accepted Answer

A)  horizontal and points right. 
B)  horizontal and points left. 
C)  zero. 
D)  vertical and points upward. 
E)  vertical and points downward. 
A)  horizontal and points right. 
B)  horizontal and points left. 
C)  zero. 
D)  vertical and points upward. 
E)  vertical and points downward.

Question 16

A girl runs around a circular track of radius R with a constant speed v. At the moment the girl has run half of the track, the magnitude of her average velocity is

Accepted Answer

A)  $\mathcal { V }$ 
B)  $0$ 
C)  2v/. $\pi$ 
D)  $2 v$ 
E)  2v. $\pi$ 
A)  $\mathcal { V }$ 
B)  $0$ 
C)  2v/. $\pi$ 
D)  $2 v$ 
E)  2v. $\pi$

Question 17

An expert marksman aims a high-speed rifle directly at the center of a nearby target. The rifle's sight has been adjusted for more distant targets. The bullet will hit the target

Accepted Answer

A)  above the center of the target. 
B)  right at the center of the target. 
C)  below the center of the target. 
D)  to the left or right of the center of the target. 
E)  at an unknown location; more information is needed to work out the answer. 
A)  above the center of the target. 
B)  right at the center of the target. 
C)  below the center of the target. 
D)  to the left or right of the center of the target. 
E)  at an unknown location; more information is needed to work out the answer.

Question 18

A girl runs around a circular track of radius R with a constant speed v. At the moment the girl has run half of the track, the magnitude of her average acceleration is

Accepted Answer

A)  v2/ $\pi$ R. 
B)  $0$ 
C)  2v2/R. 
D)  2v2/ $\pi$ R. 
E)  v2/R. 
A)  v2/ $\pi$ R. 
B)  $0$ 
C)  2v2/R. 
D)  2v2/ $\pi$ R. 
E)  v2/R.

Question 19

A projectile is fired at 25o above the horizontal. At the highest point in its trajectory, its speed is 100 m/s. If air resistance is ignored, the initial velocity had a horizontal component of

Accepted Answer

A)  0 m/s. 
B)  100 cos(25o) m/s. 
C)  100 sin(25o) m/s. 
D)  100 m/s. 
E)  100/sin(25o) m/s. 
A)  0 m/s. 
B)  100 cos(25o) m/s. 
C)  100 sin(25o) m/s. 
D)  100 m/s. 
E)  100/sin(25o) m/s.

Question 20

Two shells are fired simultaneously from the same battleship at two targets. The shells follow the trajectories shown here. Which target will be hit first?

Accepted Answer

A)  Target 1 
B)  Target 2 
C)  Both targets will be hit at the same time. 
D)  More information is needed to work out the answer. 
A)  Target 1 
B)  Target 2 
C)  Both targets will be hit at the same time. 
D)  More information is needed to work out the answer.

Exam 4: Motion in Two and Three Dimensions

Is it possible for an object moving at a constant speed around a circular path to be subject to an acceleration?

The velocity of an object with respect to reference frame A is equal to

A baseball is hit by a bat and is launched in a projectile motion at 30o above the horizontal. At the top of the baseball's trajectory

A toy car moving along the x axis at 3.0 m/s is accelerated uniformly for 4.0 s at 0.40 m/s2 along the y axis. The toy car's speed at the end of the 4.0 s is:

A student driving her car at a constant speed makes a left turn. Her bag, on the passenger seat, slides and hits the passenger door. Which statement is correct?

A basketball is shot from a free-throw range. At the top of the basketball's trajectory, its acceleration is

A child is riding on a Ferris wheel that is rotating clockwise at a constant speed. When the child is at the top of the wheel, her acceleration

A train is traveling east at 30 km/h. After it rounds a curve, it travels south at 40 km/h. The magnitude of its average acceleration is

A car travels one lap around a circular track in 120 s. The diameter of the track is 30 m. The car's average speed is

An object is undergoing uniform circular motion. Its speed is 10 m/s and the radius of its path is 15 m. When its speed is halved, its centripetal acceleration is

A yellow ball rolling rapidly along a tabletop rolls off the edge and falls to the floor. At the same instant, a blue ball having the same mass and shape as the yellow one is dropped from the same height. The ball that has the larger vertical velocity component when it hits the floor is

For the two-dimensional motion of a projectile launched from the ground, all of the following apply except

A roller coaster car travels at a constant speed on a track that forms a circular loop in a vertical plane. The car's acceleration is

A girl runs around a circular track of radius R with a constant speed v. At the moment the girl has run half of the track, the magnitude of her average velocity is

An expert marksman aims a high-speed rifle directly at the center of a nearby target. The rifle's sight has been adjusted for more distant targets. The bullet will hit the target

A girl runs around a circular track of radius R with a constant speed v. At the moment the girl has run half of the track, the magnitude of her average acceleration is

A projectile is fired at 25o above the horizontal. At the highest point in its trajectory, its speed is 100 m/s. If air resistance is ignored, the initial velocity had a horizontal component of

Two shells are fired simultaneously from the same battleship at two targets. The shells follow the trajectories shown here. Which target will be hit first?

Space, Time, and Mass

Motion Along a Straight Line

Vectors

Newtons Laws of Motion

Further Applications of Newtons Laws

Work and Energy

Conservation of Energy

Gravitation

Systems of Particles

Collisions

Rotation of a Rigid Body

Dynamics of a Rigid Body

Statics and Elasticity

Oscillations

Waves

Sound

Fluid Mechanics

The Ideal Gas

Heat

Thermodynamics

Electric Force and the Electric Charge

The Electric Field

Gauss Law

Electrostatic Potential and Energy

Capacitors and Dielectrics

Currents and Ohms Law

Direct Current Circuits

Magnetic Force and Field

Charges and Currents in Magnetic Fields

Electromagnetic Induction

Alternating Current Circuits

Electromagnetic Waves

Reflection, Refraction, and Optics

Interference and Diffraction

The Theory of Special Relativity

Quanta of Light

Spectral Lines, Bohrs Theory, and Quantum Mechanics

Quantum Structure of Atoms, Molecules, and Solids

Nuclei

Elementary Particles and Cosmology

Filters

A baseball is hit by a bat and is launched in a projectile motion at 30^o above the horizontal. At the top of the baseball's trajectory

A toy car moving along the x axis at 3.0 m/s is accelerated uniformly for 4.0 s at 0.40 m/s² along the y axis. The toy car's speed at the end of the 4.0 s is:

A projectile is fired at 25^o above the horizontal. At the highest point in its trajectory, its speed is 100 m/s. If air resistance is ignored, the initial velocity had a horizontal component of