Question

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.

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