EduNinja

Name each quantity

The equilibrium position is the central position where the resultant restoring force is zero. Displacement $x$ is the signed distance from equilibrium. Amplitude $x_0$ is the maximum magnitude of displacement.

Connect time measures

The period $T$ is the time for one complete cycle. Frequency $f$ is the number of cycles per second, so $T=1/f$ . Angular frequency is $\omega=2\pi f=2\pi/T$ , measured in radians per second.

Keep amplitude and displacement distinct

Amplitude is a non-negative fixed maximum for an ideal oscillation; displacement changes continuously between $-x_0$ and $+x_0$ . The sign of displacement identifies the side of equilibrium.

Common trap

Do not call the distance travelled in one cycle the amplitude. Amplitude is measured from equilibrium to an extreme position, not from one extreme to the other.

[ 1 ]

State the amplitude of the motion.

Recognize SHM

SHM requires a restoring acceleration $a=-\omega^2x$ about equilibrium. Track displacement, amplitude, period, frequency and angular frequency with $T=1/f=2\pi/\omega$ .

Track one cycle

At an extreme, potential energy is maximum and kinetic energy is zero; at equilibrium, kinetic energy is maximum and potential energy is minimum. Total energy remains constant in ideal SHM.

Read the motion

The gradient of a displacement–time graph is velocity. Acceleration is opposite to displacement. Use the sign of displacement and the gradient to identify direction at any instant.

Final check

Measure displacement from equilibrium, keep amplitude distinct from peak-to-peak distance, and name the relevant potential-energy form for the oscillator.

C.1.3—SHM quantities

Describe the Quantities in SHM

Retrieve the Core C.1 Simple Harmonic Motion Model

C.1.3 Exam Analysis