A crate is initially at rest and then slides down a long inclin that is 30 degrees above the horizontal. If the coefficient of kinetic friction is 0.40, the speed of the crate after 5s is ?

Answer 1

force down the plane=mgSinTheta
friction force up plalne=mu*mgCosTheta

netforce=ma
mg(sinTheta-mu*CosTheta)=ma

solve for a.
then, vf=a*time=5a