$A$ particle is thrown with any velocity vertically upward. The distance travelled by the particle in the first second of its descent is:

$A$ body is released from the top of a tower $H$ metre high. It takes $t$ seconds to reach the ground. The height of the body $\frac{t}{2}$ seconds after release is

$A$ body,thrown upwards with some velocity,reaches a maximum height of $50 \,m$. Another body with double the mass,thrown up with double the initial velocity,will reach a maximum height of............$m$.

Two balls $A$ and $B$ are thrown with the same velocity $u$ from the top of a tower of height $h$. Ball $A$ is thrown vertically upwards and ball $B$ is thrown vertically downwards. If $t_A$ and $t_B$ are the respective times taken by the balls $A$ and $B$ to reach the ground,then identify the correct statement.

$A$ very large number of balls are thrown vertically upwards in quick succession 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 is (take $g = 10\, ms^{-2}$):-

$A$ ball is thrown vertically upwards from the ground $G$ with a speed $u$. It reaches a point $B$ at a height $h$ (lower than the maximum height) after time $t_1$. It returns to the ground after time $t_2$ from the instant it was at $B$ during the upward journey. Then $t_1t_2$ is equal to