2.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{184043b7-1222-44fb-bc9f-3f484f72147b-04_675_1499_242_258}
\captionsetup{labelformat=empty}
\caption{Figure 2}
\end{figure}
Figure 2 shows a speed-time graph for a model of the motion of an athlete running a \(\mathbf { 2 0 0 m }\) race in 24 s .
The athlete
- starts from rest at time \(t = 0\) and accelerates at a constant rate, reaching a speed of \(10 \mathrm {~ms} ^ { - 1 }\) at \(t = 4\)
- then moves at a constant speed of \(10 \mathrm {~ms} ^ { - 1 }\) from \(t = 4\) to \(t = 18\)
- then decelerates at a constant rate from \(t = 18\) to \(t = 24\), crossing the finishing line with speed \(U \mathrm {~m} \mathrm {~s} ^ { - 1 }\)
Using the model,
- find the acceleration of the athlete during the first 4 s of the race, stating the units of your answer,
- find the distance covered by the athlete during the first 18s of the race,
- find the value of \(U\).