$A$ ball is dropped from a bridge $122.5\, m$ above a river. After the ball has been falling for $2\, s$,a second ball is thrown straight down after it. What must its initial velocity be so that both hit the water at the same time?.......$m/s$

$A$ body is thrown vertically up from the ground. It reaches a maximum height of $100\,m$ in $5\,sec$. After what time will it reach the ground from the maximum height position?

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 ............ $m$.

$A$ body falling from a vertical height of $10 \, m$ pierces through a distance of $1 \, m$ in sand. It faces an average retardation in sand equal to (where $g$ = acceleration due to gravity).

$A$ ball is thrown vertically downward with a velocity of $20\; m/s$ from the top of a tower. It hits the ground after some time with a velocity of $80\; m/s$. The height of the tower is $......m$ : $(g = 10\; m/s^2)$

$A$ ball is thrown vertically upwards with a velocity of $15 \ m/s$. To what maximum height will it reach? (Take $g = 10 \ m/s^2$)