$A$ stone is thrown with an initial speed of $4.9 \, m/s$ from a bridge in a vertically upward direction. It falls down into the water after $2 \, s$. The height of the bridge is .......... $m$.

Balls are thrown vertically upward in such a way that the next ball is thrown when the previous one is at the maximum height. If the maximum height is $5 \ m$,the number of balls thrown per minute will be

$A$ ball is thrown vertically upwards with an initial velocity $u$ and reaches its maximum height in $5 \,s$. The ratio of the distance travelled by the ball in the $2^{nd}$ and $7^{th}$ second is (assume $g=10 \,m/s^2$):

When a ball is dropped into a lake from a height $4.9 \, m$ above the water level,it hits the water with a velocity $v$ and then sinks to the bottom with the constant velocity $v$. It reaches the bottom of the lake $4.0 \, s$ after it is dropped. The approximate depth of the lake is ............ $m$.

$A$ stone falls freely under gravity. It covers distances $d_1$ and $d_2$ in the first $4$ seconds and the next $8$ seconds,respectively. The ratio $\frac{d_2}{d_1}$ is

$A$ ball is projected upwards from a height $h$ above the surface of the earth with velocity $v$. The time at which the ball strikes the ground is