The coefficient of static friction between the tires of a car and a horizontal road is 0.515. As the car brakes, what is the magnitude of the maximum acceleration of the car? Assume the net force on the car is the maximum static friction force.

Answer 1

The accelerating force M*a must not exceed the maxmum static friction force mus*M*g. (mus is the static friction coefficient)

Therefore

a < mus*g

Solve for the maximum acceleration a.

This assumes that the road surface is not banked, as it is on most sharp turns. When a curve is "banked", gravity helps keep the car on the road.

Answer 2

what is the net force in a rock that weighs 500N if the water it displaces is 300N

Answer 3

net force= weight-bouyancy= 500-300 N