Question

a ball is thrown vertically upwards and reaches the height of 20m and comes back . calculate initial velocity and the time which the object was in air?...​

Answer 1

Explanation:

A) The initial velocity of the ball is 20m/s :

As it reaches a maximum height of 20m

and the acceleration is 10m/s^2.

So in order to reach a height of 20m ,with an acc. in opp. direction it has to move with 20m/s

b) 20m/s

As the velocity of any object thrown upward with some speed lands on the ground with the sane speed

c) use v=u+at

0=20-10t

»t=2 sec

but this is the time it reach the max. height

so it will take 2 more sec to reach ground

» Time = 4 sec