Physics Demonstrations

Spring Mass

In this demonstration, we explore the oscillation of a mass (m) attached to a spring with spring constant (k), displaced an initial distance (A) from its equilibrium position. By Hooke's Law, the restoring force on the mass is:

F = - k x

Applying Newton's second law gives the equation of motion:

m x¨ = - k x

The solution describes simple harmonic motion:

x (t) = A cos ( ω t )

Where the angular frequency and period are:

ω = k m T = 2π ω = 2π m k

Some questions to consider while viewing the demonstration:

  • How does increasing the mass affect the period of oscillation? How does increasing the spring constant affect it?
  • The amplitude A does not appear in the formula for T. What does this tell you about the relationship between amplitude and period?
  • Identify a real-world system that behaves like a spring-mass oscillator.