$A$ body,thrown upwards with some velocity,reaches a maximum height of $50 \,m$. Another body with double the mass,thrown up with double the initial velocity,will reach a maximum height of............$m$.

$A$ ball is thrown upward from the ground with an initial speed of $v$. At the same instant, another ball is dropped from a building of height $20 \,m$. If the balls are at the same height after $0.8 \,s$, then the magnitude of $v$ is (Take, acceleration due to gravity $=10 \,ms^{-2}$) (in $\,ms^{-1}$)

$A$ body thrown vertically upwards with an initial velocity $u$ reaches maximum height in $6$ seconds. The ratio of the distances travelled by the body in the first second and the seventh second is

$A$ balloon was moving upwards with a uniform velocity of $10 \, m/s$. An object of finite mass is dropped from the balloon when it was at a height of $75 \, m$ from the ground level. The height of the balloon from the ground when the object strikes the ground was around (in $m$). (Take the value of $g$ as $10 \, m/s^2$)

$A$ diving board is at a height of $h$ from the water surface. $A$ swimmer standing on this board throws a stone vertically upward with a velocity of $16 \,ms^{-1}$. It reaches the water surface in a time of $5 \,s$. In the next $0.2 \,s$, the diver hears the sound from the water surface. What is the speed of sound (in $\,ms^{-1}$)? (Take acceleration due to gravity $g=10 \,ms^{-2}$)

$A$ person throws balls into the air vertically upward at regular intervals of time of $1 \,s$. The next ball is thrown when the velocity of the ball thrown earlier becomes zero. The height to which the balls rise is (Assume $g = 10 \,m/s^2$) (in $\,m$)