Physics
10
Rotation of a Rigid Body About a Given Fixed Line
11
⚡ Quick Summary
When a rigid body rotates about a fixed line (axis of rotation), each particle of the body moves in a circle whose center lies on the axis. Different particles move in circles of different radii depending on their distance from the axis. The planes of all these circles are parallel to each other.
None explicitly mentioned in this section.
Rotation of a Rigid Body About a Given Fixed Line
- A rigid body can be displaced such that it rotates about a fixed line.
- Each particle of the rigid body moves in a circle, with the center on the line joining the two fixed points (axis of rotation).
- The center of the circular path of a particle is at the foot of the perpendicular from the particle to this axis.
- Different particles move in different circles; the planes of all these circles are parallel to each other.
- The radii depend on the distances of the particles from this axis.
- Particles on the axis remain stationary.
- The particles closer to the axis move in smaller circles, and those farther away move in larger circles.
- Each particle takes equal time to complete its circle.
- A displacement of a rigid body in which a given line is held fixed is called rotation of the rigid body about the given line. The line itself is called the axis of rotation.