$A$ stone thrown upward with a speed $u$ from the top of a tower reaches the ground with a velocity $4 u$. The height of the tower is .........

Two stones of different masses are dropped simultaneously from the top of a building. Which of the following statements is true regarding their motion?

$A$ ball is thrown vertically upwards with a velocity of $20 \; m s^{-1}$ from the top of a multistorey building. The height of the point from where the ball is thrown is $25.0 \; m$ from the ground. How high will the ball rise above the point of projection (in $; m$)? Take $g = 10 \; m s^{-2}$.

$A$ 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 ....... $s$.

If a ball is thrown vertically upwards with speed $u$,the distance covered during the last $t$ seconds of its ascent is

Two balls $A$ and $B$ are thrown with the same velocity $u$ from the top of a tower. Ball $A$ is thrown vertically upwards and ball $B$ is thrown vertically downwards. If $t_A = 6 \ s$ and $t_B = 2 \ s$,then the velocity $u$ of each ball is ....... $m/s$.