A car of mass \(960\text{ kg}\) is moving on a straight horizontal road. There is a constant force of magnitude \(620\text{ N}\) resisting the motion of the car.

(a) Calculate the power developed by the engine of the car when it is moving at a constant speed of \(25\text{ m s}^{-1}\).

(b) Given that the power is suddenly increased by \(12\text{ kW}\), find the instantaneous acceleration of the car.