4.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{63363c3e-13fc-49a1-8cef-951e6e97e801-12_453_990_244_539}
\captionsetup{labelformat=empty}
\caption{Figure 3}
\end{figure}
A small stone is projected with speed \(65 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) from a point \(O\) at the top of a vertical cliff.
Point \(O\) is 70 m vertically above the point \(N\).
Point \(N\) is on horizontal ground.
The stone is projected at an angle \(\alpha\) above the horizontal, where \(\tan \alpha = \frac { 5 } { 12 }\)
The stone hits the ground at the point \(A\), as shown in Figure 3.
The stone is modelled as a particle moving freely under gravity.
The acceleration due to gravity is modelled as having magnitude \(\mathbf { 1 0 m ~ s } \mathbf { m ~ } ^ { \mathbf { - 2 } }\)
Using the model,
- find the time taken for the stone to travel from \(O\) to \(A\),
- find the speed of the stone at the instant just before it hits the ground at \(A\).
One limitation of the model is that it ignores air resistance.
- State one other limitation of the model that could affect the reliability of your answers.