An electric train accelerates uniformly from rest to speed of 20ms-1 which it maintains until the brakes are applied it's them brought too rest by a uniform retardation equal in magnitude to twice its former acceleration .
The total distance covered is 7.8 km and the total time taken is 7 minutes. Sketch a velocity-time diagram. Calculate 1)the time for which the train is traveling at constant speed.
2)the initial acceleration in ms^-2

Question

An electric train accelerates uniformly from rest to speed of 20ms-1 which it maintains until the brakes are applied it's them brought too rest by a uniform retardation equal in magnitude to twice its former acceleration .
The total distance covered is 7.8 km and the total time taken is 7 minutes. Sketch a velocity-time diagram. Calculate 1)the time for which the train is traveling at constant speed.
2)the initial acceleration in ms^-2