- A train travels along a straight horizontal track between two stations \(A\) and \(B\).
The train starts from rest at station \(A\) and accelerates uniformly for \(T\) seconds until it reaches a speed of \(20 \mathrm {~ms} ^ { - 1 }\)
The train then travels at a constant speed of \(20 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) for 3 minutes before decelerating uniformly until it comes to rest at station \(B\).
The magnitude of the acceleration of the train is twice the magnitude of the deceleration.
- On the axes below, sketch a speed-time graph to illustrate the motion of the train as it moves from station \(A\) to station \(B\).
\includegraphics[max width=\textwidth, alt={}, center]{84c0eead-0a87-4d87-b33d-794a94bb466c-02_670_1422_813_312}
If you need to redraw your graph, use the axes on page 3
Stations \(A\) and \(B\) are 4.8 km apart. - Find the value of \(T\)
- Find the acceleration of the train during the first \(T\) seconds of its motion.
Only use these axes if you need to redraw your graph. \({ } _ { O } ^ { \substack { \text { speed }
\left( \mathrm { ms } ^ { - 1 } \right) } }\)