posted by aok on .
Derek the drunk driver drives his car off the road, onto a gravel strip next to the road. Derek does not have anti-lock brakes, so his wheels lock when he enters the gravel area, and the car slides to a halt. Derek's car is traveling at a speed of 20m/s when it enters the gravel strip, and comes to a stop after sliding through the gravel for 40m. The mass of the car (including Derek) is 700kg.
What is the amount of work done on Derek's car by the gravel strip?
If the gravel strip is completely flat, what is the coefficient of kinetic friction between the gravel and Derek's car's tires?
vf^2=Vi^2+2ad and from that solve for acceleration, a.
but a= forcefriction/mass= mu*g
if a= mu*g, you can solve for mu.
work done: mu*mg*distance