$A$ stone dropped from the top of a tower is found to travel $\left(\frac{5}{9}\right)$ of the height of the tower during the last second of its fall. The time of fall is ....... $s$.

From the top of a tower,a ball is thrown vertically upward which reaches the ground in $6 \, s$. $A$ second ball thrown vertically downward from the same position with the same speed reaches the ground in $1.5 \, s$. $A$ third ball released from rest from the same location will reach the ground in ........ $s$.

If a body is thrown up with the velocity of $15 \, m/s$,then the maximum height attained by the body is .......... $m$ $(g = 10 \, m/s^2)$.

$A$ 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

$A$ balloon starts rising from the ground from rest with an upward acceleration of $2 \, m/s^2$. Just after $1 \, s$,a stone is dropped from it. The time taken by the stone to strike the ground is nearly ....... $s$.

An iron ball and a wooden ball of the same radius are released from a height $h$ in vacuum. The time taken by both of them to reach the ground is