Re: A problem: linear momentum, angular momentum, dissipation

["D.V.N.Sarma" <narayana@HD1.VSNL.NET.IN>]

On 5 Aug 2001, at 2:51, John S. Denker wrote:

> Where does this k come from?
 From the statement of the problem. It is the coefficient of friction.

> It's highly non-obvious that the distance is ka/2.
> It's not even true, unless you add a lot of implausible assumptions.

In a frame moving with the cube, if we apply the condition net
torque about the center of the cube is equal to zero (because the
cube is not rotating in this frame) we get that the torque due to
frictional forces i.e., kmga/2 is equal to mgx where x is the
separation between the lines of action of mg and normal reaction.
This gives x=ka/2.

regards,
sarma.

regards,
sarma.