Finding coefficien of kinetic friction

[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.

 

[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.