A.1 Kinematics and A.2 Forces and momentum

1 Preview Question

A car accelerates uniformly from rest to 25 m/s in 8.0 s. It then continues at this constant speed for 12 s before decelerating uniformly to rest in 5.0 s. Which of the following velocity–time graphs best represents the motion of the car?

• A A graph with a straight line from (0,0) to (8,25), a horizontal line from (8,25) to (20,25), and a straight line back to (25,0).
• B A graph with a curved line increasing non-linearly until 8 s, then decreasing sharply to 0 by 25 s.
• C A graph with constant acceleration beyond 8 s, showing velocity continuously rising past 25 m/s.
• D A graph with linear increase to 25 m/s in 8 s, immediately dropping vertically to zero at 20 s.

*The correct answer is not shown in the preview.