Question

A ball is thrown vertically upward and reaches a height of 45m find the velocity with which it was thrown​

Answer 1

Let the velocity of projection is u, and the final velocity at the top height will be zero.

The velocity of the projection is given as,

v

2

=u

2

−2gh

u=

2×10×45

u=30m/s

The time when the velocity of ball become to half velocity of projection is given as,

v=u−gt

15=30−10×t

t=1.5s

Thus, the time when the velocity of ball become to half velocity of projection is 1.5s.