Question

A ball thrown vertically upwards with a velocity 20m/s.It takes 4 seconds to return to its original am position .Draw its v-t graph?

Answer 1

I tried this:

Explanation:

In A the ball is thrown upwards with positive velocity `20m/s`. In B it reaches the maximum height with velocity zero. In C it reaches the original position, completing the total time of `4s`, having reversed velocity equal to the (negative) original initial one. During the entire movement the acceleration `g` is constant pointing downwards (negative) so that the slope (=acceleration) of our line is negative.