In Fig. 6-21, a slide-loving pig slides down a certain 37° slide in twice the time it would take to slide down a frictionless 37° slide. What is the coefficient of kinetic friction between the pig and the slide?

Answer 1

down a frictionless slide: mg*SinTheta=ma

down a friction slide: mgSinTheta-mu*mg*CosTheta=ma

so if the time for friction is 2x, then its acceleration is half of the original a.

mgSinTheta-mu*mg*CosTheta=1/2 *(sinTheta)mg

solve for mu.

Answer 2

0.377