$A$ man in a balloon rising vertically with an acceleration of $4.9 \, m/s^2$ releases a ball $2 \, s$ after the balloon is let go from the ground. The greatest height above the ground reached by the ball is .......... $m$ :-

$A$ ball is thrown straight upward from the ground with a speed of $20 \,m/s$. The ball is caught on its way down at a point $5 \,m$ above the ground. The time taken by the ball during the entire trip is (assume $g = 10 \,m/s^2$):

Two bodies $A$ (of mass $1\,kg$) and $B$ (of mass $3\,kg$) are dropped from heights of $16\,m$ and $25\,m$ respectively. The ratio of the time taken by them to reach the ground is:

Consider the acceleration,velocity,and displacement of a tennis ball as it falls to the ground and bounces back. The directions of which of these change during the process?

$A$ ball is dropped from the roof of a tower of height $h$. The total distance covered by it in the last second of its motion is equal to the distance covered by it in the first three seconds. The value of $h$ in meters is $(g = 10\,m/s^2)$.

$A$ ball falls vertically downward and bounces off a horizontal floor. The speed of the ball just before reaching the floor $(u_1)$ is equal to the speed just after leaving contact with the floor $(u_2)$,where $u_1 = u_2$. The corresponding magnitudes of accelerations are denoted respectively by $a_1$ and $a_2$. The air resistance during motion is proportional to speed and is not negligible. If $g$ is the acceleration due to gravity,then: