posted by bob .
a 3000 pound car is parked on a hill at an angle of elevation of 16 degrees. how much force must the brakes exert to keep the car from rolling down the hill?
Wc=3000Lbs*0.454kg/Lb * 9.8N/kg=13,348N
= Wt. of car.
Fp = 13348*sin16 = 3679 N. = Force parallel to the hill.
Fe - Fp = m*a
Fe - 3679 = m*0 = 0.
Fe = 3679 N. = Force exerted by brakes.