Physics

Problem

Which one of the following gives the magnitude of the kinetic friction acting on a block of mass

m

that is sliding down a rough plane inclined at an angle

\theta

to the horizontal? (

\mu_k

is the coefficient of kinetic friction.) a)

\mu_k m g \sin\theta

m g \sin\theta

\mu_k m g \cos\theta

\frac{\mu_k m g}{\cos\theta}