Question

A ball is thrown vertically upwards. It goes to a height 20 m and then returns to the ground. Taking acceleration due to gravity g to be 10 m s-2, find the following variables: (a) The initial velocity of the ball (b) The final velocity of ball on reaching the ground and (c) The total time of the journey of the ball.

Answer 1

Answer:

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