$A$ body is thrown vertically upwards. At half of the maximum height,its velocity is $10 \ m/s$. What is the maximum height attained by the body? (Take $g = 10 \ m/s^2$)

$A$ boy throws balls into the air at a regular interval of $2 \, s$. The next ball is thrown when the velocity of the first ball is zero. How high does the ball rise above his hand (in $, m$)? [Take $g = 9.8 \, m/s^2$]

$A$ parachutist after bailing out falls $50\, m$ without friction. When the 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 (in $, m$)?

$A$ balloon rises from rest with a constant acceleration $g/8$. $A$ stone is released from it when it has risen to height $h$. The time taken by the stone to reach the ground is

$A$ horizontal bridge is built across a river. $A$ student standing on the bridge throws a small ball vertically upwards with a velocity $4\,m s^{-1}$. The ball strikes the water surface after $4\,s$. The height of the bridge above the water surface is $......\,m$ (Take $g=10\,m s^{-2}$).

The velocity of a body upon reaching the point from which it was projected upwards is: