Project 1 Midpoint Review

A car traveling in a straight line has a velocity of 5 m/s at some instant. After 2 s, its velocity is 11 m/s. What is its average acceleration in this time interval?

• 3 m/s2
• 5.5 m/s2
• 2.5 m/s2
• 5 m/s2

A car accelerates from rest at 2 m/s². How much time does it need to attain a speed of 10 m/s?

• 10 s

• 8 s

• 5 s

• 2 s

If the acceleration of an object is zero at some instant in time, what can be said about its velocity at that time?

• It is zero.
• It is changing.
• It is positive.
• More info is needed.

A car is at the edge of its driveway facing away from the street. Its owner pulls the car into the driveway. As the car starts from rest and gains speed up to 5 mph pulling into the driveway, its

• acceleration points to the front of the car and its velocity points to the front.
• acceleration points to the back of the car and its velocity points to the back.
• acceleration points to the front of the car and its velocity points to the back.
• acceleration points to the back of the car and its velocity points to the front.

A rocket-driven sled running on a straight, level track has been used to study the physiological effects of large accelerations on astronauts. One such sled can attain a speed of 100 m/s in 3 s starting from rest. How far does the sled travel in 3 s, starting from rest?

• 300 m
• 50 m
• 100 m
• 150 m

A 2000 kg car has a speed of 10 m/s when it hits a tree. The tree doesn’t move and the car comes to rest. Find the change in kinetic energy of the car.

• 200000 J
• 100000 J
• 20000 J
• 10000 J

A 2000 kg car has a speed of 10 m/s when it hits a tree. The tree doesn’t move and the car comes to rest. Find the amount of work done by the car as its front is pushed in.

• 200000 J
• 20000 J
• 100000 J
• 10000 J

A 2000 kg car has a speed of 10 m/s when it hits a tree. The tree doesn’t move and the car comes to rest. Find the magnitude of the force of the collision if it pushed the front of the car in by 50 cm.

• 100000 N
• 10000 N
• 20000 N
• 200000 N

A complete CER answer to an open-ended question will have a minimum of __ sentences.

• 1
• 2
• 3
• 4

A claim is a single sentence that directly answers the question.

• true
• false