Question

The velocity of a ball is thrown up is 20 meters/second. It attains zero velocity after 3.5 seconds. What is the average acceleration of the ball during its upward flight?

Answer 1

average acceleration = (velocity final - velocity initial)/time
in the same way that average velocity = (final position - initial position)/time

Answer 2

(Vf - Vi)/t we're assuming that it is decelerating at a constant rate

0m/s - 20 m/s =- 20 m/s,- 20 m/s /3.5s = -5.713 m/s^2