1. The problem statement, all variables and given/known data A 2.1 x 10^3kg car starts from rest at the top of a 5.0m long driveway that is inclined at 20degrees with the horizontal. If an average friction force of 4.0 x 10^3N impedes the motion, find the speed of the car at the bottom of the driveway. 2. Relevant equations Work-energy theorum: Wnet = delta KE 3. The attempt at a solution I don't know where to start. Do I need to consider potential energy too? or just kinetic energy? What I did is to start with this equation: Wnet = KEf - KEi Since the car started from rest, KEi = 0. Therefore, Wnet = 1/2mvf^2. Solve for vf. Am i right? It's on an incline, do I need to include the x component of gravitational force?