A body of mass m slides down a rough plane of inclination `alpha` . If `mu` be the coefficient of friction the acceleration of the body will be ________ .

Options

A. g sin `alpha`
B. g `mu cos alpha`
C. g ( sin `alpha - mu cos alpha` )
D. g (cos `alpha -mu sin alpha` )

Answer

C

Explanation

Here R = mg cos `alpha`
and mg sin `alpha- mu `R = ma
Therefore , acceleration
`a=(mgsinalpha-muR)/(m)= (mgsinalpha-muxxmgcosalpha)/(m)`
= g`(sinalpha-mucosalpha)`