5．\(v \left( \mathrm {~m} \mathrm {~s} ^ { - 1 } \right) ^ { \wedge }\) Figure 4 The velocity－time graph in Figure 4 represents the journey of a train \(P\) travelling along a straight horizontal track between two stations which are 1.5 km apart．The train \(P\) leaves the first station，accelerating uniformly from rest for 300 m until it reaches a speed of \(30 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) ．The train then maintains this speed for \(T\) seconds before decelerating uniformly at \(1.25 \mathrm {~m} \mathrm {~s} ^ { - 2 }\) ，coming to rest at the next station．
（a）Find the acceleration of \(P\) during the first 300 m of its journey．
（b）Find the value of \(T\) ． A second train \(Q\) completes the same journey in the same total time．The train leaves the first station，accelerating uniformly from rest until it reaches a speed of \(V \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and then immediately decelerates uniformly until it comes to rest at the next station．
（c）Sketch on the diagram above，a velocity－time graph which represents the journey of train \(Q\) ．
（d）Find the value of \(V\) ．