Chapter 6 of 10All chapters
Chapter 6 of 10
Work and energy
A shortcut past the forces.
The energy method
Work is force times distance along the force. Because energy is conserved, comparing energy at the start and end often answers a question without tracking the motion between.
- Kinetic energy is half mass times velocity squared.
- Gravitational potential energy is mass times g times height.
Why it is easier
Energy is a scalar, so there are no directions to resolve. A roller coaster speed at the bottom follows from the drop height alone, whatever shape the track had.