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

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

A body dropped from the top of a tower clears $7/16^{th}$ of the total height of the tower in its last second of flight. The time taken by the body to reach the ground is……..$s$

A ball is dropped from the top of a building of height $80 \,m$. At same instant another ball is thrown upwards with speed $50 \,m / s$ from the bottom of the building. The time at which balls will meet is …….. $s$

From the top of a $64\, ft$ high tower, a stone is thrown upwards vertically with the velocity of $48\, ft/s$. The greatest height (in $ft$) attained by the stone, assuming the value of the gravitational acceleration $g\, = 32\, ft/s^2$, is