A ball is thrown upwards. It takes $4\,sec$ to reach back to the ground. Its initial velocity is……..$ms^{-1}$

A ball is dropped from a building of height $45 \,m$. Simultaneously another ball is thrown up with a speed $40\, ms^{-1}$. Calculate the relative speed of the balls as a function of time.

The ratio of the distances travelled by a freely falling body in the $1^{\text {st }}, 2^{\text {nd }}, 3^{\text {rd }}$ and $4^{\text {th }}$ second :

A particle is projected up with an initial velocity of $80\;ft/\sec $. The ball will be at a height of $96\;ft$ from the ground after

A particle is dropped vertically from rest from a height. The time taken by it to fall through successive distances of $1\, m$ each will then be