$A$ ball is thrown upwards. Its height varies with time as shown in the graph. If the acceleration due to gravity is $g = 7.5\, m/s^2$,then the height $h$ is.........$m$.

Two balls are released from the same position at a height of $500 \ m$ above the ground, one after the other, with an interval of $1 \ s$. What is the distance between the two balls when the first ball hits the ground (in $m$)? (Acceleration due to gravity $g = 10 \ m/s^2$)

Two stones of masses $m_1$ and $m_2$ (such that $m_1 > m_2$) are dropped $\Delta t$ time apart from the same height towards the ground. At a later time $t$,the difference in their speed is $\Delta v$ and their mutual separation is $\Delta s$. While both stones are in flight:

Which of the following statements is correct?

$A$ stone dropped from the top of the tower touches the ground in $4 \, s$. The height of the tower is about..........$m$.

$A$ particle is projected upwards. The times corresponding to height $h$ while ascending and while descending are $t_1$ and $t_2$ respectively. The velocity of projection will be