A 3 kg toy car rests st the top of a 0.45 meter ramp. What is its gravitational potential energy?

gravitational potential energy : P

Gravity : g

Mass : m

height : h

P = mgh = 3 x 9.8 x 0.45 = 13.23 Joule

Potential energy is work, from the known formula

W = Fd (work = force x distance)

W = P (in case of potential energy height change)

F is the force acting on the body in case of ideal ramp, the only force acting is the weight of the body

F = mg (not just as the force is mg (Newton) gravity effect)

d is the displacement in direction of force, as we have considered the force to be the weight not it's component in direction of the ramp, the change in displacement is the change in height so

d = h

W = Fd = (F = mg) x (d = h) = mgh

W = mgh = P