Unit Overview

Simple Harmonic Motion Overview

AP Physics 1· 5 min read 📊 5-8% of the AP Physics 1 exam

1. Unit at a Glance

This unit is built around simple harmonic motion (SHM). Learning builds incrementally from defining and describing SHM (via the restoring force $F = - k x$ , period, and frequency) to analyzing its energy transformations.

By working through the sub-topics, you will connect energy conservation to the period, frequency, and amplitude of oscillating systems such as mass-springs and simple pendulums.

Below are the sub-topics that make up this unit, ordered logically for learning:

AP Physics 1 Kinematics of Simple Harmonic Motion

Introduces SHM basics, period, frequency, amplitude, and kinematic descriptions of mass-spring and pendulum systems.

★★⏱ 12 min

AP Physics 1 Energy in Simple Harmonic Motion

Explores energy conservation and transformation in oscillating SHM systems.

★★⏱ 10 min

2. Common Pitfalls

Wrong move:

Confusing any periodic motion with simple harmonic motion.

Why:

Only periodic motion with a restoring force proportional to displacement from equilibrium qualifies as SHM.

Correct move:

Confirm SHM by checking that net force follows $F_{n e t} = - k x$ .

Wrong move:

Treating a large-amplitude pendulum as SHM.

Why:

The simple-pendulum SHM result relies on the small-angle approximation; at large angles the restoring force is no longer proportional to displacement.

Correct move:

Only apply $T = 2 π L / g$ for small angular displacements.

3. Quick Reference Cheatsheet

Concept	Key Formula/Relationship
SHM Net Restoring Force	$F_{n e t} = - k x$
Period of Mass-Spring System	$T = 2 π \frac{m}{k}$
Period of Simple Pendulum	$T = 2 π \frac{L}{g}$
Total Energy of SHM	$E = \frac{1}{2} k A^{2}$

What's Next

Start your learning with the foundational kinematics of simple harmonic motion, the first sub-topic in this unit. Once you complete both sub-topics on simple harmonic motion, you will move on to the next AP Physics 1 unit, Unit 8: Fluids.