The driver of a 1560 kg automobile traveling at 24 m/s on a leve, paved road hits the brakes to stop for a red light. determine the distance needed to stop the car if the coefficient of friction between the car tires and the road is .80
-one of the steps required of me to obtain the answer is: Apply newtons second law in component form to the situation.
i am at a loss please help me
"Newton's second law in component form" is just
F = m a in the horizontal direction of motion.
F is the braking force, M*g*Uk
where Uk is the coefficient of kinetic friction.
M*g*Uk = M a means that
a = g*Uk is the acceleration rate.
a*(stopping time) = (initial velocity)
Stopping time = Vo/(g*Uk)
Stopping distance = Avg velocity*(Stopping time)
= Vo^2/(2*g*Uk)
Note that the mass cancels out, and is not needed.