# Conservation of Angular Momentum and Vectors

• esmeralda4
In summary, the conversation discusses the concept of conservation of angular momentum, using the example of a person sitting on a rotating chair holding a rotating wheel. The total angular momentum is conserved by adding together the momentum of the two bodies. There is confusion about what happens to the wheel's speed when the person changes their position, and also about the direction of the vector of angular momentum. Additional resources are suggested for further explanation and understanding.
esmeralda4
Hi there,

I'll come straight out with this, I'm really struggling to understand the conservation of angular momentum.

A common example involves someone sitting on a rotating chair holding a rotating wheel. If the wheel is held so that the axis of rotation is vertical then the person rotates in the opposite direction.

The total angular momentum is conserved by adding together the momentum of the two bodies.

Does this mean that when the wheel is turned 90 degrees then it will spin faster since the person on the chair is no longer rotating? The wheel would have to spin faster to conserve angular momentum since there is now only one body rotating right? If this is wrong can someone help to explain please?

Also I don't understand what it means to say the vector of angular momentum is perpendicular to the plane of rotation. Does that mean there is a force in this direction? If not then why not since momentum includes a mass and velocity?

Hope that makes sense.

Many thanks

Or this: http://www.triumphofmind.net/2011/07/angular-momentum-is-easy-or-physics-of.html

Last edited by a moderator:

## What is conservation of angular momentum?

Conservation of angular momentum is a fundamental law of physics that states that the total angular momentum of a closed system remains constant over time. This means that the amount of rotational motion in a system does not change unless an external torque is applied.

## How is angular momentum calculated?

Angular momentum is calculated by multiplying the moment of inertia (a measure of an object's resistance to rotational motion) by the angular velocity (the rate at which an object rotates around a fixed axis) and the direction of rotation.

## What is a vector?

A vector is a mathematical quantity that has both magnitude and direction. In the context of angular momentum, vectors are used to represent the direction and magnitude of rotational motion.

## How does conservation of angular momentum relate to vectors?

Conservation of angular momentum is related to vectors because angular momentum is a vector quantity. This means that it has both magnitude and direction, and must be considered in vector form when applying the law of conservation of angular momentum.

## What are some real-life examples of conservation of angular momentum?

Some examples of conservation of angular momentum in everyday life include the spinning of a top, the rotation of a planet around its axis, and the movement of a spinning ice skater pulling in their arms to increase their rate of rotation.

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