⚛ Physics LabOscillations · v0.27 beta

DYNAMICS · CLASSICAL OSCILLATORS

Oscillations: Spring and Pendulum

Explore harmonic motion, damping and energy transformations. Compare a linear spring with a nonlinear pendulum, distinguishing exact laws from small-angle approximations.

Physical Parameters

kg
N/m
N·s/m
m
m/s
m
m/s²
N·m·s
°
rad/s
s

For the spring, x = 0 m is the equilibrium position; viscous damping is Fᵥ = −bv. No periodic external driving force.

Simulation and Force Diagram

The pendulum has the same scale on both axes: angles are drawn geometrically without distortion. Torque arrows are schematic.

Position / Angle—
Velocity—
Acceleration—
Net Force / Torque—
Kinetic Energy—
Potential Energy—
Mechanical Energy—
Dissipated Energy—
Energy Residual—
Reference Period—
Motion Regime—
Radial Rod Reaction—

Synchronized Graphs

Click a graph or enter an exact time to update the diagram, values and worked solution. The dashed pendulum comparison uses a linearized model and may be inaccurate at large amplitudes.

Selected Time: 0.00 s

Position / Angle vs Time

Velocity vs Time

Acceleration vs Time

Kinetic, Potential and Mechanical Energies

Mechanical Energy, Dissipation and Balance

Values Table

t (s)Typeq (m or rad)v (m/s or rad/s)a (m/s² or rad/s²)K (J)U (J)E (J)Q (J)Residual (J)Force (N or N·m)

Comma-separated CSV with decimal points and SI units.

Model Assumptions

Spring-Mass: a point mass on a horizontal guide and an ideal Hookean spring with constant k; linear damping Fᵥ = −bv. No dry friction, impacts or external driving forces. An exact analytical solution is used for all three damping regimes.

Pendulum: a point mass attached to a rigid, inextensible, massless rod; frictionless pivot when c = 0 and uniform gravity. Viscous torque is τᵥ = −cω. The nonlinear equation with sin θ is integrated numerically; complete rotations are also possible.

The pendulum period T₀ = 2π√(L/g) is a small-angle approximation, not the exact period of large-amplitude oscillations. With damping, the motion is not strictly periodic.

Energies are K and U, with U = 0 J at equilibrium. Cumulative dissipation Q is nonnegative, and the energy balance is E(t) + Q(t) = E(0). Numerical integration error is reported as a residual.

FROM THE MODEL TO THE RESULTS

Step-by-Step Calculations

General equations, SI substitutions and intermediate steps.

One left-aligned equation per line. MathML fallback is provided when MathJax is unavailable. Rounding affects display only.

by Andrea Minini