Question

1) A car moving along a straight stretch of road at 60 mph [26.7 meters/sec]. The driver makes slams on his breaks locking them so that the car skids to a stop. Assume a constant braking force due to friction, and a kinetic friction coefficient of 0.70 between the tires and the road: (a) calculate the braking distance from the instant that the brakes were applied, (b) how much work did the friction do in stopping the car?

Answer 1

vf^2=vi^2+2ad
where a= force/mass=-.7mg/m= -.7g
solve for distance d