$A$ 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 $,m$)?

$A$ balloon starts rising from the ground with an acceleration of $1.25\, m/s^2$. After $8\,s$,a stone is released from the balloon. The stone will $(g = 10\, m/s^2)$:

$A$ body at rest falls through a height $h$ with velocity $V$. If it has to fall down further for its velocity to become $3V$,the distance travelled in that interval is: (in $h$)

Two spherical balls having equal masses with a radius of $5 \, \text{cm}$ each are thrown upwards along the same vertical direction at an interval of $3 \, \text{s}$ with the same initial velocity of $35 \, \text{m/s}$. These balls collide at a height of $\ldots \ldots \ldots \, \text{m}$. (Take $g = 10 \, \text{m/s}^2$)

$A$ body is projected vertically upwards. It reaches a point at a height $h$ above the point of projection after some time with a speed of $8 \,m/s$. The maximum height reached by the body is (Acceleration due to gravity $g = 10 \,m/s^2$). (in $m$)

$A$ ball is dropped on the floor from a height of $10 \, m$. It rebounds to a height of $2.5 \, m$. If the ball is in contact with the floor for $0.01 \, s$,the average acceleration during contact is: