in case of a sliding body with friction not sufficient to prevent slipping..is there any ways of computing the kinetic energy of the body other than finding out velocity of centre of mass and angular velocity..i mean to say by the work done by the forces applying F.d?

Question

anonymous · Answer

more specifically work done by kinetic friction in the form of F.d ?

vincent-lyon.fr · Answer

Work done by kinetic friction can be computed and interpreted this way, but not easily. 

You need to find its power first, which is $\large\vec F .\vec v_{ slip}$, in which $\large\vec v_{ slip}$ is the slipping velocity, that is the relative velocity between the two surfaces in contact. 

This dot product will always be negative. 

I you have solved the problem and know the expression of $\large\vec v_{ slip}(t)$, you can integrate the formula above and find the work done by friction. 

$\large d=\int v_{ slip}(t)dt$, is the distance the surfaces in contact have slipped relative to one another. 

Work done is $\large W=-Fd$

anonymous · Answer

ok thanx soo much! :D