Question about angular momentum given some reference point.

[Subliminal]

L=vmr (angular momentum)

 

If an object 'm' is moving and has a reference point 'p' that is a distance r from the object, is the angular momentum of the object its capacity to rotate a light plank fixed to point

 

I know the torque is the change in angular momentum over time, but is L simply tangential velocity times mass times r or angular velocity times mass times r? I don't know what it is....

 

Angular velocity is theta/t = w, so is does L = wmr and not vmr?

[swansont]

L = mvr (as a vector it's r x p) or Iw where I is the moment of inertia for the rotation.

 

wmr has the wrong units so we know it can't be right.

[Endercreeper01]

It would not be wmr and it would instead be wmr² because w is the angular velocity, and the velocity is v=wr. Since L=mvr, then it is also L=wmr² because v=wr, and if we plug that into the equation, we get L=(wr)mr, and then we get wmr².

[Subliminal]

L = mvr (as a vector it's r x p) or Iw where I is the moment of inertia for the rotation.

 

wmr has the wrong units so we know it can't be right.

[decraig]

L=vmr (angular momentum)

 

If an object 'm' is moving and has a reference point 'p' that is a distance r from the object, is the angular momentum of the object its capacity to rotate a light plank fixed to point

 

 

To be precise, r is the perpendicular distance to the ray traced by the velocity vector of the center of mass of the object (within Newtonian physics).

Edited December 2, 2013 by decraig