- How much work is done by gravity?
- How much work is done by the normal force?
- How much work is done by friction?
- What is the total work done?
Here’s How to Crack It
- Remember that the force that’s directly responsible for pulling the box
down the plane (F||) is the component of the gravitational force that’s parallel
to the ramp: Fw sin θ = mg sin θ (where θ is the incline angle). This
component is parallel to the motion, so the work done by gravity is:
Wby gravity = (mg sinθ)d = (40 kg)(10 N/kg)(sin 40°)(10 m) = 2,400
J
