$A$ body is projected vertically upward with a velocity of $20 \, m/s$ from the top of a tower of height $200 \, m$. With what velocity will it strike the ground (in $m/s$)? (Take $g = 10 \, m/s^2$)

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:

$A$ ball is thrown vertically upwards with a velocity of $15 \ m/s$. To what maximum height will it reach? (Take $g = 10 \ m/s^2$)

$A$ man is standing on top of a building $100\, m$ high. He throws two balls vertically,one at $t = 0$ and the other after a time interval $\Delta t$ (less than $2\, s$). The second ball is thrown at a velocity half that of the first. The vertical gap between the first and second ball is $15\, m$ at $t = 2\, s$. The gap is found to remain constant. Calculate the velocity with which the balls were thrown and the exact time interval between their throws.

$A$ tennis ball is released from a height $h$ and after freely falling on a wooden floor,it rebounds and reaches a height $\frac{h}{2}$. The velocity versus height of the ball during its motion may be represented graphically by (graphs are drawn schematically and not to scale):

If a stone is released from a balloon rising with acceleration $a$ at the instant when its velocity is $v$,then immediately after release,the acceleration and velocity of the stone are