What is angular momentum?

Answer:

Momentum is the product of mass and the velocity of the object. Any object moving with mass possesses momentum.

Angular Momentum

The equivalent of linear momentum in rotational motion is angular momentum. It is the property of a rotating body given by the product of a moment of inertia and the angular velocity of a rotating object.
The Angular Momentum of a rotating body is proportional to its mass and to how rapidly it is turning.

• In addition, the angular momentum depends on how the mass is distributed relative to the axis of rotation: the further away the mass is located from the axis of rotation, the greater the angular momentum.
• A flat disk such as a record turntable has more angular momentum than a tall cylinder of the same mass and velocity of rotation.
• Like linear momentum, angular momentum is a vector quantity, and its conservation implies that the direction of the spin axis tends to remain unchanged.
• For this reason, the spinning top remains upright whereas a stationary one falls over immediately.

Angular Momentum Formula

Angular momentum can be experienced by an object in two situations. They are:

Where,

• \(\begin{array}{l}\vec{L}\end{array} \)
  is the angular velocity
• r is the radius (distance between the object and the fixed point about which it revolves)
• \(\begin{array}{l} \vec{p}\end{array} \)
  is the linear momentum.
• I is the rotational inertia.
• \(\begin{array}{l} \vec{\omega }\end{array} \)
  is the angular velocity.

Examples

1. Ice-skater
2. Gyroscope

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Articles to Explore:

1. What is momentum? Write its SI unit. Interpret force in terms of momentum. Represent the following graphically (a) momentum versus velocity when mass is fixed. (b) momentum versus mass when velocity is constant.
2. Write the relation between angular momentum and torque.