$A$ very large number of balls are thrown vertically upwards in quick succession in such a way that the next ball is thrown when the previous one is at the maximum height. If the maximum height is $5\, m$,the number of balls thrown per minute is (take $g = 10\, ms^{-2}$):-

$A$ body is falling freely from a point $A$ at a certain height from the ground and passes through points $B, C$, and $D$ (vertically as shown below) such that $BC = CD$. The time taken by the particle to move from $B$ to $C$ is $2 \ s$ and from $C$ to $D$ is $1 \ s$. The time taken to move from $A$ to $B$ in seconds is

$A$ 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 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............$m$.

An object is thrown vertically upwards. At its maximum height,which of the following quantities becomes zero?

An object thrown vertically up from the ground passes a height of $5 \, m$ twice in an interval of $10 \, s$. The total time of flight is ........ $s$.