Angular Momentum Experiment – For Schools, Teachers, and Students
Definition
Angular momentum is a measure of the quantity of rotation an object possesses, taking into account its mass, shape, and rotational velocity. It is a vector quantity, represented by the symbol L.
Mathematically, angular momentum is defined as the cross product of the position vector (r) and the linear momentum (p):
L = r × p = r × m v
This concept is demonstrated in Dencity – physics lab online simulations app to enhance interactive learning.
Theory
Angular momentum plays a crucial role in rotational mechanics and is analogous to linear momentum in translational motion. It depends on three key factors:
- Mass (m): Contributes to an object’s inertia.
- Velocity (v): Determines the linear momentum of the object.
- Perpendicular distance (r): The moment arm, measured from the axis of rotation.
For a rigid body rotating about a fixed axis, angular momentum can be expressed using moment of inertia (I) and angular velocity (ω):
L = I ω
Conservation of Angular Momentum:
Angular momentum remains conserved in an isolated system where no external torque acts. This is expressed as:
If τ_ext = 0, then L_initial = L_final
This principle explains how rotational speed changes when an object’s shape or mass distribution is altered.
Real-World Applications
The concept of angular momentum has several real-life applications, including:
- Satellite & Spacecraft Stabilization: Used in gyroscopes and reaction wheels to control orientation.
- Planetary Rotation: Planets and stars maintain their spin due to conservation of angular momentum.
- Sports Science: Figure skaters, gymnasts, and divers use angular momentum to control spins and rotations.
- Energy Storage: Flywheels in power systems store and release rotational energy.
- Online Science Lab: Helps students simulate and understand rotational mechanics interactively.
Observations and Key Learnings
- Increasing mass (m) or velocity (v) increases angular momentum.
- Increasing the perpendicular distance (r) increases angular momentum.
- If moment of inertia (I) increases while angular velocity (ω) remains constant, angular momentum increases.
- Conservation of angular momentum explains why a skater pulls in their arms to spin faster.
