$A$ ball is dropped vertically from height $h$ and is bouncing elastically on the floor (see figure). Which of the following plots best depicts the acceleration of the ball as a function of time?

Two balls $A$ and $B$ are thrown with the same velocity $u$ from the top of a tower. Ball $A$ is thrown vertically upwards and ball $B$ is thrown vertically downwards. If $t_A = 6 \ s$ and $t_B = 2 \ s$,then the velocity $u$ of each ball is ....... $m/s$.

Water drops are falling from a nozzle of a shower onto the floor,from a height of $9.8\, m$. The drops fall at a regular interval of time. When the first drop strikes the floor,at that instant,the third drop begins to fall. Locate the position of the second drop from the floor when the first drop strikes the floor. (In $m$)

Balls are thrown vertically upward 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 will be

Assertion $(A)$: The displacement of a vertically projected body during the last second of its upward motion is $\frac{g}{2}$.
Reason $(R)$: For a vertically projected body,the acceleration decreases gradually and becomes $\frac{g}{2}$ during the last second of upward motion.

$A$ ball is projected vertically upwards from the ground. It reaches a height $h$ in time $t_1$,continues its motion,and then takes a time $t_2$ to reach the ground. The height $h$ in terms of $g, t_1$,and $t_2$ is ($g =$ acceleration due to gravity).