Angular Momentum
Rotating Weights
A demonstrator holds weights and rotates on a platform.
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- Rotating platform
- A pair of weights
A person, rotating on a platform with a weight in either hand, retracts and extends arms to demonstrate a change in the angular speed as the radius of the rotation of the weights changes.
Bicycle Wheel
A demonstrator holds a bicycle wheel and rotates on a platform.
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- Rotating platform
- A bicycle wheel
A person holding a bicycle wheel and standing on a freely rotating platform will demonstrate various ways of conservation of angular momentum by spinning, stopping, and inverting the wheel.
Spinning Phonograph Disk
A disk with a string at its center spins while it swings.
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- A large phonograph disk
- A piece of string
A phonograph disc is suspended at its center on a string. When given a spin and allowed to swing as a pendulum, the plane of the disc, and therefore, the direction of the angular momentum, remains constant.
Cat-Twist
A mechanical model of a cat is used to demonstrate how an inverted cat dropped with zero angular momentum can still land on its feet.
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- Mechanical "Galli" cat
- Soft landing surface
In order to demonstrate how a cat can turn over over in midair and land on its feet without a torque, a mechanical model has been constructed and is demonstrated in this movie. This model was constructed from copper tubing, springs, and other metal parts. When this "mechanical cat" is released from an upside down position with its back to the ground, it flips over to land on its feet. The net torque and the net angular momentum remain zero throughout the entire time..