$A$ ball projected vertically upwards with a velocity '$v$' passes through a point $P$ in its upward journey in a time of '$x$' seconds. From there,the time in which the ball again passes through the same point $P$ is

$A$ ball is thrown up vertically with a certain velocity so that it reaches a maximum height $h$. Find the ratio of the times at which it is at height $\frac{h}{3}$ while going up and coming down respectively.

Reaction time: When a situation demands our immediate action,it takes some time before we really respond. Reaction time is the time a person takes to observe,think,and act. For example,if a person is driving and suddenly a boy appears on the road,then the time elapsed before he slams the brakes of the car is the reaction time. Reaction time depends on the complexity of the situation and on an individual.
You can measure your reaction time by a simple experiment. Take a ruler and ask your friend to drop it vertically through the gap between your thumb and forefinger. After you catch it,find the distance $d$ travelled by the ruler. In a particular case,$d$ was found to be $21.0 \; cm$. Estimate the reaction time in seconds. (in $; s$)

$A$ body falls freely from the top of a tower. It covers $36\%$ of the total height in the last second before striking the ground level. The height of the tower is........$m$

From a balloon moving upwards with a velocity of $12\,ms^{-1}$,a packet is released when it is at a height of $65\,m$ from the ground. The time taken by it to reach the ground is...........$s$ $(g = 10\,ms^{-2})$.

The velocity-time curve for a body projected vertically upwards is: