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Oscillations

Four topics build the physics of oscillation, from what makes motion repeat to where its energy goes. Defining simple harmonic motion identifies the one condition behind every oscillator: a restoring force proportional to displacement. Frequency and period set the timing of a spring or a pendulum, and reveal what the timing does and does not depend on. Representing and analyzing simple harmonic motion tracks position, velocity, and acceleration as they trade off a quarter cycle apart. Energy of simple harmonic oscillators follows the steady exchange between kinetic and potential energy as the system swings between its turning points.

Topics
Equations For every problem in this unit
Period and frequency
$T = \dfrac{1}{f}$
Spring oscillator period
$T_s = 2\pi\sqrt{\dfrac{m}{k}}$
Pendulum period (small swings)
$T_p = 2\pi\sqrt{\dfrac{\ell}{g}}$
Position, released from maximum
$x = A\cos(2\pi f t)$
Position, released from equilibrium
$x = A\sin(2\pi f t)$
Restoring force
$F_s = -k\,\Delta x$
Spring potential energy
$U_s = \tfrac{1}{2}k(\Delta x)^2$
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 7 tools