== UNIT 3: WORK, ENERGY, AND POWER ==
Work done: W = F*d*cos(θ) where θ is angle between force and displacement
Only force component parallel to displacement does work
Negative work: force opposes motion (friction, air resistance)
Work-energy theorem: net work = change in kinetic energy
Kinetic energy: KE = 0.5*m*v^2
Conservative force: work path independent (gravity, spring)
Non-conservative force: work path dependent (friction)
Gravitational PE: PE_g = m*g*Δh (only height change matters)
Spring PE: PE_s = 0.5*k*x^2 where x is displacement from equilibrium
Mechanical energy: E = KE + PE
Conservation of energy: E_initial = E_final (if only conservative forces)
Non-conservative work: W_nc = ΔKE + ΔPE
Power: P = W/t (average) or P = F*v (instantaneous)
Energy transfer via work
Energy transfers between forms, never created/destroyed