Indicate which statement is correct:

- speed never changes
- At the highest point in its motion, the ball's velocity is zero.
- At the highest point in its motion, the ball's velocity is not zero
- none of the above

Question 2: Assume a student throws a ball vertically downward with a velocity of 10 m/s.

If air friction is considered negligable then calculate the speed of the ball one second later.

- 9.8 m/s
- 20 m/s
- 19.8 m/s
- 18.8 m/s

Question 3: Suppose you throw a ball vertically with a velocity of 10 m/s.

Approximately, when will it reach its highest height?

- 3 s.
- 2 s.
- 5 s.
- 1 s.

Question 4: Assume a television screen fall down from rest at a great height.

Calculate the speed after it has fallen for 5 seconds where air resistance is considered negligible.

- 49 m/s
- 48 m/s
- 47m/s
- 46m/s

Explanation: acceleration (a) = speed (v) divided by elapased time (t), which implies that v = a × t = 9.8 m/s

Question 5: Assume a box of 5 kg is dropped from a building and hits the ground in 7 s.

Calculate the time it takes for a 10-kg box to hit the ground where air resistance is considered negligible.

- 14 s
- 10 s
- 5 s
- 7 s

Explanation: since air resistance is zero then the time would stay the same.

Question 6: If a rocket is fired from a fighter jet and assuming that air resistance is negligible.

Which statement is correct about the rocket.

- The rocket stops immediately.
- Its speed doubles every second.
- Its speed increases at 9.8 m/s.
- none of the above.

Question 7: If you throw a ball up in the air.

Indicate the status of the ball when it reaches its highest point.

- acceleration is zero.
- speed doubles every second.
- velocity is halved and the acceleration is downward.
- velocity is zero and the acceleration is downward.
- none of the above.

Question 8: If you throw a ball up in the air with an initial velocity of 20m/s.

Calculate the ball's velocity after 4 seconds.

- − 19.2 m/s
- 0 m/s
- 19.2 m/s
- 20 m/s

Explanation: 20 m/s - 4 s × 9.8 m/s

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Date of last modification: Summer , 2019