$A$ ball is thrown upward from the top of a building at an angle of $30^{\circ}$ to the horizontal with an initial speed of $15 \,ms^{-1}$. If the ball hits the ground after $3 \,s$, then the height of the building is (acceleration due to gravity $= 10 \,ms^{-2}$): (in $\,m$)

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

Three balls,$A, B$ and $C$ are released and all reach the point $X$ (shown in the figure). Balls $A$ and $B$ are released from two identical structures,one kept on the ground and the other at height $h$ from the ground as shown in the figure. They take time $t_A$ and $t_B$ respectively to reach $X$ (time starts after they leave the end of the horizontal portion of the structure). The ball $C$ is released from a point at height $h$,vertically above $X$ and reaches $X$ in time $t_C$. Choose the correct option.

An archer shoots an arrow from a height of $4.2 \text{ m}$ above the ground with a speed of $40 \text{ m/s}$ at an angle of $30^{\circ}$ with the horizontal, as shown in the figure. Determine the total horizontal distance $R$ covered by the arrow when it hits the ground. (Take $g = 10 \text{ m/s}^2$)

An airplane is flying at a height of $1960 \, m$ with a horizontal velocity of $360 \, km/hr$. When the airplane is directly above point $A$,a body is dropped from it. How much time (in $sec$) will it take for the body to reach the ground?

An aeroplane moving horizontally at a speed of $200 \; m/s$ and at a height of $8 \; km$ is to drop a bomb on a target. At what horizontal distance from the target should the bomb be released? (Take $g = 9.8 \; m/s^2$)