A body of mass 0.3 kg is taken up an inclined plane of length 10m and height 5 m and then allowed to slide down to bottom again. Find work done by frictional force over the round trip if mu=0.15.

A body of mass 0.3 kg is taken up an inclined plane of length 10m and

1.	A body of mass 0.3 kg is taken up an inclined plane of length 10m and height 5 m and then allowed to slide down to bottom again. Find work done by frictional force over the round trip if mu=0.15.
Answer» Solution : `sintheta=(5)/(10)=(1)/(2)=sin.(pi)/(6)` so, `theta=(pi)/(6)` WORK done by frictional FORCE, `W=2vecf.vecl` `W=2flcosalpha(alpha=pi,cosalpha=-1)` `W=-2fl=-2muRl=-2mumgcosthetal` `W=-2xx0.15xx0.3xxcos.(pi)/(6)xx10xx9.8` `=-7.6J`