Question

A skier of mass m kis down a 30 degree slope. By measuring her acceleration a, the coefficient of kinetic friction mk between the skis and the snow can be calculated. Show that mk=(g sin 30-a)/(g cos 30)

SO I know that sin 30 = opp/hyp and cos 30 = adj/hyp. Ffr=MFnor, so normal force = Fg..F=ma..so a = F/m...I just don't know how to show that they are all connected

Answer 1

You need to draw a force diagram. The skiers weight mg is down. Drawing it into two components, one normal to the hill, and one down the slope.

Fdownslope=mgsinTheta
Fnormal=mgcosTheta

Now, you can write the force equation (down the slope as +)

mgsinTheta- mu(mgcosTheta)=ma

Solve for mu.