A cat walks in a straight line, which we shall call the x-axis, with the positive direction to the right. As an observant physicist, you make measurements of this cat's motion and construct a graph of the feline's velocity as a function of time (Fig. E2.30). (a) Find the cat's velocity at t = 4.0 s and at t = 7.0 s.

The position-time graph for a moving box is shown below.

(a) What is the box's average velocity from 0 to 5s?
(b) What is the box's average velocity from 0 to 8s?
(c) What is the box's velocity in the interval where it's moving fastest?

The position-time graph for a ball on a track is shown below.
(a) What is the ball's velocity at 4s?
(b) At what time(s) is the ball approximately travelling at -10m/s?
(c) From t = 3 to 7s, what is the sign of the acceleration?