$A$ ball is projected from a point $O$ as shown in the figure. It will strike the ground after ........ $s$ $\left(g=10 \, m/s^2\right)$.

An aeroplane flying $490 \, m$ above ground level at $100 \, m/s$ releases a block. How far on the ground will it strike (in $km$)?

$A$ man runs across the roof of a tall building and jumps horizontally with the hope of landing on the roof of the next building,which is at a lower height than the first. If his speed is $9 \, m/s$,the horizontal distance between the two buildings is $10 \, m$,and the height difference is $9 \, m$,will he be able to land on the next building? (Take $g = 10 \, m/s^2$)

$A$ cricket bowler releases the ball in two different ways:
$(a)$ giving it only horizontal velocity,and
$(b)$ giving it horizontal velocity and a small downward velocity.
The speed $V_s$ at the time of release is the same. Both are released at a height $H$ from the ground. Which one will have greater speed when the ball hits the ground? Neglect air resistance.

$A$ bowling machine placed at a height $h$ above the earth's surface releases different balls with different angles but with the same velocity $10 \sqrt{3} \text{ m s}^{-1}$. All these balls' landing velocities make angles of $30^{\circ}$ or more with the horizontal. Find the height $h$ (in meters) (acceleration due to gravity $g = 10 \text{ m s}^{-2}$).

$A$ child stands on the edge of a cliff $10 \ m$ above the ground and throws a stone horizontally with an initial speed of $5 \ m/s$. Neglecting air resistance,the speed with which the stone hits the ground will be $.......... \ m/s$ (given,$g = 10 \ m/s^2$).