Question

A ball is throw n vertically upward with 20 ms-1

standing on the roof of his house 10 m high.

Calculate the time after which the ball will hit the ground. (take g = 10 ms-2)​

Answer 1

Explanation:

v=u+at

take v=0

u=-gt

20=10t

t=2sec

s=ut+1/2at^2

s=20*2-1/2*10(2)^2

s=20mt

s=1/2at^2

40=1/2(10)t^2

t=8^1/2

total time T=2+(8)^1/2=2(1+2^1/2)