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

3.1

Translational Kinetic Energy

Work and the Work-Energy Theorem

Potential Energy

Conservation of Energy

Power

Lesson

Diag

locked

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

Challenge bank

1 / 60

60 open-ended problems.

Read the question, work it out, then flip the card to compare your reasoning to the worked solution. Mark each card so you can return to the ones that still bite.

Question

Tap card to reveal explanation

Worked solution

Tap card to return to question

Cumulative assessment

Test the unit.

Twenty mixed items pulled from across all 5 topics. Identifies which misconceptions still bite when you cannot see which topic the question came from.