physics
posted by johnny .
a slide loving pig slides down a certain 44° slide in twice the time it would take to slide down a frictionless 44° slide. What is the coefficient of kinetic friction between the pig and the slide?

If the time is doubled by the presence of friction, the acceleration is reduced by a factor 4. (That is because (1/2)a*t^2 remains the same). The friction is therefore 3/4 of the component of the weight down the plane. (That leaves a net accelerating force that is 1/4 of the weight component down the slide).
M g cos 44 * uk = (3/4) M g sin 44
Solve for uk, the kinetic friction coefficient.
uk = (3/4) tan 44