A 2.10x10^3 kg car starts from rest at the top of a 5.8 m long driveway that is sloped at 25° with the horizontal. If an average friction force of 4.0X10^3 N impedes the motion, find the speed of the car at the bottom of the driveway.

im using the equation -(frictional force)=PE(gravitional initial)+KE(final) im getting the answer wrong and am wondering if i need to take 5.8sin25 for y in the PE part.
i just Really Need Help