If a freely falling body travels in the last second a distance equal to the distance travelled by it in the first three seconds,the time of the travel is ........ $sec$.

$A$ man throws a ball vertically upward and it rises through $20 \; m$ and returns to his hands. What was the initial velocity $(u)$ of the ball and for how much time $(T)$ it remained in the air? $[g = 10 \; m/s^2]$

$A$ stone is dropped from a height $h$. Simultaneously,another stone is thrown up from the ground which reaches a height $4h$. The two stones cross each other after time:

$A$ window is $50\,cm$ long. $A$ stone is falling from a height of $40\,cm$ above the window. It crosses the window in

$A$ body falls from a large height. The ratio of distance traveled in each time interval $t_0$ during $t = 0$ to $t = 3\, t_0$ of the journey is

Two bodies of masses $m_1$ and $m_2$ are dropped from two different heights $h_1$ and $h_2$ respectively. The ratio of the times taken by the two masses to touch the ground is (neglect air resistance)