Finding coefficien of kinetic friction

1. Oct 6, 2012

sjcorona

A slide loving pig slides down a 35 degree slide in twice the time it would taken to slide down a frictionless 35 degree slide. What is the coefficient of kinetic friction between the pig and slide?

So with the frictionless slide I found ax=8.03m/s^2 but without velocity or the length of the slide I'm not sure how to find time. So i shifted to the slide with friction,

Fy= n-mgsin(35)
0=n-mgsin(35)
N=mg sin(35)

Fx=-fk+mgcos(35)
Fx= mg(-μksin(35))+(cos(35))
M*ax=^

Ax=g(-μksin(35))+(cos(35))

I definitely can't use the same value of acceleration right? Because the first acceleration assumed no opposing force.

2. Oct 6, 2012

LawrenceC

Pick an arbitrary length for the slide. You'll find that it'll cancel out of the equations. Use the time-distance formula for constant accelerations. Determine acceleration for each case first.