A-level Mathematics/Edexcel/Mechanics 1/Statics of a particle

$$$$A car of total mass 1200 kg is moving along a straight horizontal road at a speed of 40 m/s,when the brakes are fully applied ,they exert a constant force and the car comes to rest after travelling a distance of 80m.The resistance to motion from all factors other than the brakes is assumed to be constant and of magnitude 500N.Find the magnitude of the force exerted by the brakes when fully applied.