$A$ ball is dropped from a height $h$ above the ground. Neglecting air resistance,its velocity $(v)$ varies with its height $(y)$ above the ground as:

Two balls $A$ and $B$ are placed at the top of a $180 \,m$ tall tower. Ball $A$ is released from the top at $t = 0 \,s$. Ball $B$ is thrown vertically downward with an initial velocity $u$ at $t = 2 \,s$. Both balls meet at a point $100 \,m$ above the ground. Find the value of $u$ in $m \,s^{-1}$. [Use $g = 10 \,m \,s^{-2}$]

$A$ 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 projected upwards from a height $h$ above the surface of the earth with velocity $v$. The time at which the ball strikes the ground is

Two bodies are thrown simultaneously from a tower with the same initial velocity $v_0$: one vertically upwards,the other vertically downwards. The distance between the two bodies after time $t$ is

$A$ ball is dropped from the top of a tower of $100 \, m$ height. Simultaneously,another ball is thrown upward from the bottom of the tower with a speed of $50 \, m/s$ $(g = 10 \, m/s^2)$. They will cross each other after . . . . . . $s$.