A parachutist after bailing out falls $50\, m$ without friction. When parachute opens, it decelerates at $2\, m/s^2$. He reaches the ground with a speed of $3\, m/s$. At what height, did he bail out ?……..$m$

An object start sliding on a frictionless inclined plane and from same height another object start falling freely

A projectile is fired vertically upwards with an initial velocity $u$. After an interval of $T$ seconds a second projectile is fired vertically upwards, also with initial velocity $u$.

A body is released from a great height and falls freely towards the earth. Another body is released from the same height exactly one second later. The separation between the two bodies, two seconds after the release of the second body is…….$m$

A boy is standing on top of a tower of height $85 \,m$ and throws a ball in the vertically upward direction with a certain speed. If $5.25$ s later he hears the ball hitting the ground, then the speed with which the boy threw the ball is ………. $m / s$ (take, $g=10 \,m / s ^2$ and speed of sound in air $=340 \,m / s$ )