A. How much impulse is needed to stop a 1,500 kg car that travels at 10.0 m/s?
B. How much force of friction is needed to stop the car in 5.0 s? What coefficient of friction is needed to stop the car in this time?
Impulse = force * time = change in momentum
= 1500 * 10
B. Two ways
1. impulse = force* time = 15000
so force = 15000/5 = 3,000 Newtons
2. stop distance = average speed * time = 5*5 =25 meters
force * 25 meters = initial kinetic energy
25 F = (1/2) 1,500 * 100
F = 3,000 Newtons again
Now mu
mu m g = F
mu = 3,000 / [ 1500*9.81 ]