View Full Version : Physics, work energy theorems
 
 leoman
Dec 1, 2013, 04:43 PM
A 450 kg car is driving at 60mph. The car hits a patch of ice and hits brakes. If coefficient of friction between tires and ice is 0.07, how far will the car slide before coming to a full stop. And how mechanical energy was taken by friction?
 ebaines
Dec 6, 2013, 07:05 AM
Use equivalence of work and energy.  The initial kinetic energy of thecar is:
 
 
KE = \frac 1 2 m v^2
 
 
This energy must be opposed by the work of friction that slows the car to zero.  The work done by friction is:
 
 
W = Fd
 
 
You can calculate F given the car's weight and coefficient of friction.  So now you have everything you need to calculate the distance.  As for the second part of the question - I've already given you a good hint for that.