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Work, Energy, and Power

Five topics on energy. Kinetic energy as the scalar that tracks motion, work as the bridge that adds or removes it, gravitational and spring potential energy stored in interactions, conservation as the master accounting rule for mechanical energy, and power as the rate of energy transfer.

Topics
Equations For every problem in this unit
Kinetic energy
$K = \tfrac{1}{2} m v^2$
Work, single force
$W = F d \cos\theta$
Work-energy theorem
$\Delta K = W_{\text{net}}$
Gravitational PE
$\Delta U_g = m g \Delta y$
Spring PE
$U_s = \tfrac{1}{2} k x^2$
Average power
$P_{\text{avg}} = \dfrac{W}{\Delta t}$
Instantaneous power
$P_{\text{inst}} = F v \cos\theta$
Pythagorean
$a^2 + b^2 = c^2$
Sine, opp / hyp
$\sin\theta = \dfrac{a}{c}$
Cosine, adj / hyp
$\cos\theta = \dfrac{b}{c}$
Tangent, opp / adj
$\tan\theta = \dfrac{a}{b}$
Unit 3 tools