$A$ balloon is at a height of $81\, m$ and is ascending upwards with a velocity of $12\, m/s$. $A$ body of $2\, kg$ weight is dropped from it. If $g = 10\, m/s^2$,the body will reach the surface of the earth in ......... $s$.

$A$ 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 . . . . . . $s$.

$A$ body is thrown vertically upward at $t = 0$. It is at a height $80 \ m$ at instants $t_1$ and $t_2$. Also,it is at a height $60 \ m$ at instants $t'_1$ and $t'_2$. Then:

$A$ parachutist,after bailing out,falls $20\,m$ without friction. When the parachute opens,it decelerates at $2\,m/s^2$. He reaches the ground with a speed of $4\,m/s$. At what height did he bail out (in $,m$)?

When a ball is thrown up vertically with velocity $V_o$,it reaches a maximum height of $h$. If one wishes to triple the maximum height,then the ball should be thrown with what velocity?

$A$ tennis ball is released from a height $h$ and after freely falling on a wooden floor,it rebounds and reaches a height $\frac{h}{2}$. The velocity versus height of the ball during its motion may be represented graphically by (graphs are drawn schematically and not to scale):