A car starts from rest and moves in a straight line with constant acceleration \(a \text{ m s}^{-2}\) for a distance of 50 m. The car then travels with constant velocity for 500 m for a period of 25 s, before decelerating to rest. The magnitude of this deceleration is \(2a \text{ m s}^{-2}\).

(a) Sketch the velocity-time graph for the motion of the car.

(b) Find the value of \(a\).

(c) Find the total time for which the car is in motion.