6.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{cf960066-46b8-42a3-8a8b-d8deb76e7c70-11_694_1004_264_529}
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\caption{Figure 4}
\end{figure}
A ball is projected from a point \(A\) which is 8 m above horizontal ground as shown in Figure 4. The ball is projected with speed \(u \mathrm {~m} \mathrm {~s} ^ { - 1 }\) at an angle \(\theta ^ { \circ }\) above the horizontal. The ball moves freely under gravity and hits the ground at the point \(B\). The speed of the ball immediately before it hits the ground is \(2 u \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
- By considering energy, find the value of \(u\).
The time taken for the ball to move from \(A\) to \(B\) is 2 seconds. Find
- the value of \(\theta\),
- the minimum speed of the ball on its path from \(A\) to \(B\).