SHM Calculator

Simple Harmonic Motion

Calculate the position, velocity, and acceleration of an object undergoing simple harmonic motion at any given time.

Last updated: March 2026 | By ForgeCalc Engineering

Position (x)
1.000
Meters (m)
Velocity (v)
0.000 m/s
Acceleration (a)
-39.478 m/s²

What is Simple Harmonic Motion?

Simple Harmonic Motion (SHM) is a type of periodic motion where the restoring force is directly proportional to the displacement and acts in the opposite direction. Common examples include a mass on a spring, a simple pendulum, and the vibration of atoms in a crystal.

In SHM, the object oscillates around a central equilibrium position. The motion is characterized by its amplitude (maximum displacement), frequency (number of oscillations per second), and phase (the starting position of the oscillation).

The Formulas

Position

x(t) = A cos(ωt + φ)

Velocity

v(t) = -Aω sin(ωt + φ)

Acceleration

a(t) = -Aω² cos(ωt + φ)

Frequently Asked Questions

What is Angular Frequency (ω)?

Angular frequency (ω = 2πf) represents the rate of change of the phase of the oscillation in radians per second. It is a key parameter in the trigonometric functions describing SHM.

Why is acceleration negative?

In SHM, acceleration is always proportional to displacement but in the opposite direction (a = -ω²x). This is because the restoring force always pulls the object back toward the equilibrium position.

What is the 'Phase Constant' (φ)?

The phase constant (or phase shift) determines the starting position of the object at t=0. If φ=0, the object starts at its maximum positive displacement (A).

Is a real pendulum SHM?

A real pendulum only undergoes SHM for 'small angles' (typically less than 15°). At larger angles, the restoring force is no longer strictly proportional to the displacement, and the motion becomes more complex.

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