Question

Use the graph below. Describe the speed of the remote-control car over time.

Answer 1

It's pretty simple. What you should tell is:
The car has lost half of it's speed for first 3 seconds of movement (from 4 mi/h down to 2 mi/h). Then it became moving in 2.5 times faster for next 2 seconds (from 2 mi/h up to 5 mi/h) and after that it was moving at constant speed (5 mi/h).