Unit 3: Work, Energy, and Power

Unit 3 replaces forces with energy. Work is force times displacement in the direction of the force (area under a force-position graph), and the net work on an object equals its change in kinetic energy. Track energy in a system: gravitational potential energy (mgh near Earth), spring potential energy (½kx²), and energy dissipated by friction. When only conservative forces act, mechanical energy is conserved. Power is the rate of energy transfer, P = ΔE/Δt = Fv.