$A$ stone dropped from the top of a tower of height $300 \; m$ splashes into the water of a pond near the base of the tower. When is the splash heard at the top,given that the speed of sound in air is $340 \; m s^{-1}$ (in $; s$)? $(g = 9.8 \; m s^{-2})$

$A$ body is dropped from a height $h$. If it acquires a momentum $p$ just before striking the ground,then the mass of the body is

The effective acceleration of a body,when thrown upwards with acceleration $a$,will be:

$A$ ball (initially at rest) is released from the top of a tower. The ratio of work done by the force of gravity,in the first,second,and third seconds is

$A$ body is projected vertically upward with a speed of $40 \, m/s$. The distance travelled by the body in the last second of its upward journey is ........... $m$. [Take $g = 9.8 \, m/s^2$ and neglect the effect of air resistance]

When a ball is dropped into a lake from a height $4.9 \, m$ above the water level,it hits the water with a velocity $v$ and then sinks to the bottom with the constant velocity $v$. It reaches the bottom of the lake $4.0 \, s$ after it is dropped. The approximate depth of the lake is ............ $m$.