7.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{0a4e4cdd-bec4-4059-b9f7-9ce00bc34b71-24_629_1029_251_461}
\captionsetup{labelformat=empty}
\caption{Figure 3}
\end{figure}
A ball is projected with speed \(40 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) from a point \(P\) on a cliff above horizontal ground. The point O on the ground is vertically below P and OP is 36 m . The ball is projected at an angle \(\theta ^ { \circ }\) to the horizontal. The point Q is the highest point of the path of the ball and is 12 m above the level of P. The ball moves freely under gravity and hits the ground at the point R , as shown in Figure 3. Find
- the value of \(\theta\),
- the distance OR ,
- the speed of the ball as it hits the ground at R.