Question 2.1

• You wake up in your dorm, walk 1 km to class, and then walk back to your dorm and go to sleep. What was the magnitude of your displacement?
• 1 km
• 2 km
• zero

Mia is cycling along a straight stretch of track. Her speed is a steady 12 m/s. Which position-versus-time graph is not possible for the description of Mia’s motion?

A

B

C

D

Question 2.2

When do objects A and B have the same velocity?

1. t = 0 s
2. t = 1 s
3. t = 3 s
4. t = 5 s
5. Objects A and B never have the same velocity

Question 2.3

If the Position versus Time graph of an object moving in 1D is a straight line, what does this mean?

1. The object is not moving
2. The object is moving with a constant velocity
3. The object is moving with a constant acceleration

Question 2.4

x

t

A hockey puck shot into a goal has a velocity vs time graph as shown. Which of the lettered position vs time graphs best matches the motion?

Question 2.5

Acceleration Direction

• A car starts from rest, then drives to the right. It speeds up to a maximum speed of 30 m/s. It coasts at this speed for a while, then the driver hits the brakes, and the car slows down to a stop.
• While it is speeding up, what is the direction of the acceleration vector of the car?
• to the right.
• to the left.
• zero.

v

Question 2.6

Acceleration Direction

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• While the car is coasting, what is the direction of the acceleration vector of the car?
• to the right.
• to the left.
• zero.

v

Question 2.7

Acceleration Direction

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• While the car is slowing down, what is the direction of the acceleration vector of the car?
• to the right.
• to the left.
• zero.

v

Question 2.8

A

B

C

Question 2.9

You are traveling at an initial velocity of v₀ = 30 m/s. At position x₀ = 0 you apply the brakes, which gives you a constant acceleration of a = –10 m/s². How far do you travel before stopping? (Final velocity v = 0.)

1. 10 m
2. 15 m
3. 30 m
4. 45 m
5. 90 m

Question 2.10

1. 40 m/s, West
2. 20 m/s, West
3. zero
4. 20 m/s, East
5. 40 m/s, East

• You are on an Eastbound subway train going at 20 m/s.
• You notice the Westbound train on the other track.
• Relative to the ground, that Westbound train has a speed of 20 m/s.
• What is the velocity of the Westbound train as measured by you?

Question 2.11

Question 2.12

Question 2.13

A 600 g basketball and a 60 g tennis ball are dropped from rest. As they fall to the ground, air resistance is negligible.�Which of the following statements is true for the balls as they fall?

1. The acceleration of the basketball is 10 times greater than the acceleration of the tennis ball
2. The accelerations of the basketball and the tennis ball are the same.
3. The acceleration of the basketball is slightly greater than the acceleration of the tennis ball

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Question 2.14

A 600 g basketball and a 60 g tennis ball are dropped from rest. As they fall to the ground, air resistance is negligible.�Which of the following statements is true for the balls as they fall?

1. The force of gravity is 10 times greater on the basketball than on the tennis ball
2. The force of gravity is the same on both balls
3. The force of gravity is slightly larger on the basketball than on the tennis ball

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Question 2.15

• You toss a ball straight up in the air.
• Immediately after you let go of it, what forces are acting on the ball?
• Note, please choose ALL the answers that might apply here (do not neglect air resistance)
• [For full marks you must select all the correct responses, and none of the incorrect responses]

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1. The downward force of gravity from the Earth (a.k.a. “weight”).
2. An upward throwing force from your hand.
3. A small downward force from air resistance.
4. An upward inertial force carrying the ball forward along its trajectory.

Question 2.16

A

B

C

Question 2.17