Conservation of Angular Momentum and Vectors

[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

 

[UltrafastPED]

Try this: https://www.khanacademy.org/science/physics/torque-angular-momentum/torque-tutorial/v/conservation-of-angular-momemtum

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