An out-of-control truck with a mass of 5000kg is travelling at 35.0m/s (about 80mi/h) when it starts descending a steep (15 degrees), downward incline or slope. The incline is icy, so the coefficient of friction is 0.30. Use the work-energy theorem to determine how far the truck will skid. Assume it locks its brakes and skids the whole way before it comes to rest.

Question

I'm not good with Work-Energy Theorem:(

Answer 1

N is given by mg cos (angle) = 5000 kg x 9.8 m/s^2 x cos (15) = 47330 N

So Ff = 47330 x 0.30 = 14,200 N energy of the truck is 1/2 (mv^2) = 3,062,500 J
14,200 x = 3,062,500
x=253.7 m