Questions: Acceleration: How Velocity Changes

Question 1

A car goes from 0 m/s to 20 m/s in 5 seconds. What is its acceleration?

• A. 4 m/s²
• B. 100 m/s²
• C. 20 m/s²
• D. 25 m/s²

Answer: (A)

Acceleration = change in velocity / time = (20 - 0) / 5 = 4 m/s².

Question 2

An object moving at constant velocity has an acceleration of zero.

• T. True
• F. False

Answer: True

Acceleration is the rate of change of velocity. If velocity is not changing — same speed, same direction — then acceleration is zero.

Question 3

A ball is thrown straight up. At the very top of its path, what is its acceleration?

Model answer: 9.8 m/s² downward (the acceleration due to gravity), even though its velocity is momentarily zero.

Gravity acts on the ball throughout its flight. At the top, velocity is zero for an instant, but acceleration due to gravity never stops.