Unit Overview

Simple Harmonic Motion and Waves Overview

AP Physics 1· 5 min read 📊 12-16% of the overall AP Physics 1 exam

1. Unit at a Glance

This unit is structured around two core connected themes: the behavior of simple harmonic motion systems, and the properties of mechanical waves that propagate through media. Learning builds incrementally from describing SHM to extending periodic motion concepts to traveling and standing waves.

By working through the sub-topics, you will connect energy conservation to SHM dynamics, learn how to describe wave behavior, and apply the superposition principle to explain interference and standing waves, which are key to understanding sound and many real-world systems.

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

AP Physics 1 Wave Types and Basic Properties

Introduces transverse vs longitudinal waves, wavelength, frequency, and the fundamental wave speed equation.

★⏱ 9 min

AP Physics 1 Wave Interference and Superposition

Covers the superposition principle and explains constructive and destructive wave interference.

★★★⏱ 11 min

AP Physics 1 Sound Waves

Introduces sound as a longitudinal pressure wave, covering pitch, intensity, and basic sound properties.

★★★⏱ 10 min

AP Physics 1 Standing Waves

Explores standing wave formation on strings and in pipes, and calculating harmonic frequencies.

★★★★⏱ 14 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:

Assuming wave speed depends on wave frequency or wavelength.

Why:

Wave speed is determined solely by the properties of the medium it travels through.

Correct move:

Use $v = f λ$ to relate variables, but remember $v$ is fixed for a given medium.

Wrong move:

Mixing up boundary conditions for standing waves in closed-end vs open-end pipes.

Why:

Closed-end pipes have different harmonic sequences than open-end pipes, due to different node/antinode positions.

Correct move:

Draw boundary conditions first before calculating harmonic frequencies.

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	$T = 2 π \frac{L}{g}$
Fundamental Wave Speed Relation	$v = f λ$
Standing Waves on Fixed String	$f_{n} = \frac{n v}{2 L}, n = 1, 2, 3...$
Standing Waves in Closed-End Pipe	$f_{n} = \frac{n v}{4 L}, n = 1, 3, 5...$

What's Next

Start your learning with the foundational kinematics of simple harmonic motion, the first sub-topic in this unit. Once you complete all sub-topics on simple harmonic motion and waves, you will move on to the next AP Physics 1 unit covering torque and rotational motion.