rolling and sliding objects
- From: "katy" <mcld@xxxxxxxxxxxxxxx>
- Date: 1 May 2006 15:48:40 -0700
I'm having some problems with rolling and sliding objects..
I have an homogeneous sphere with radius of 10 cm.
It is moving in an horizontal and flat superficie until point A with
a constant velocity of 5m/s,
then from point A until point B the superficie is rough and the
coeficient of kinetic friction is 0.1.
In B the sphere start rolling without sliding.
The following diagram tries to explain the sphere path:
____A /\/\/\/\/\/\ B
The question is:
Find the kinetic energy in B
the mass of the sphere is iqual to 5/9.8 ~= 0.51
In B the sphere is not sliding and is only rolling, so that
Kinetic energy in B = Kinetic rotational energy in B = 1/2 I w^2
where I is the momentum of inertia that is equal to 2/5 M R^2
Ekb=1/2 *2/5 *M*R^2 * w^2
So, my problem is how can i found w?
i thouth in the formula v=w *r
But, in B the sphere is not sliding so, v = 0
Can somebody help me please?