physics
posted by steve .
If a car is accelerating downhill under a net force of 3,674N, what force must the brakes exert to cause the car to have a constant velocity?

Well,
If the accelerating force is 3674N, The brakes must cancel that force. 
F = ma means F is the NET force so if a is to be zero then F must be zero so you must brake with a force of 3 674 N so the overall force is zero and a = 0