Axis of Rotation: The axis of rotation is an imaginary line around which a rigid body rotates. It is a fundamental concept in rotational motion. Every point on the rigid body moves in a circle centered around this axis.
Formula for Rotational Motion: The rotational motion of a rigid body is described by various equations, and one fundamental formula relates angular displacement (θ), angular velocity (ω), and angular acceleration (α):
θ=ωt+1/2αt2
Where:
- θ is the angular displacement,
- ω is the angular velocity,
- α is the angular acceleration,
- t is the time.
Real Life Examples
Following are real life examples of rigid body and respective axis of rotation.
| Rigid Body | Axis of Rotation | Description |
|---|---|---|
| Spinning Wheel (e.g., Bicycle Wheel) | Axle of the wheel | As the wheel spins, each point on the wheel undergoes circular motion around this axis. |
| Gymnast in a Tuck Position | Imaginary line through the center of mass | When a gymnast tucks into a somersault, the body can be considered a rigid body, rotating around this axis. |
| Earth's Rotation | North and South poles (Earth's axis) | Earth itself can be treated as a rigid body, rotating around its axis. This rotation is responsible for day and night cycles. |
| Record Player Turntable | Center spindle of the turntable | As a record spins on a turntable, each point on the record undergoes circular motion around the center spindle. |
| Diving Somersault | Imaginary line through the diver's center of mass | During a somersault in diving, the diver's body acts as a rigid body, rotating around an axis through the center of mass. |
| Rotating Spacecraft | The spacecraft's central axis | Satellites or spacecraft often rotate around their central axis for stabilization or specific observational requirements. |
| Wind Turbine Blades | Center axis of the turbine | The blades of a wind turbine rotate around a central axis, converting wind energy into rotational motion to generate electricity. |