Physics Problem?

Question

A 20-kg girl slides down a playground slide that is 3.2 meters high. When she reaches the bottom of the slide, her speed is 1.3 m/s. (a) How much energy was dissipated by friction? (b) If the slide is inclined at 20 degrees, what is the coefficient of friction between the girl and the slide?

Answer 1

If she starts from rest, the loss in PE minus the ending KE is equal to the loss due to friction

20*9.81*3.2-.5*20*1.3^2=f*d
where f*d is the work of friction
a) 611 J was lost to friction

b) 611=20*9.81*cos(20)*µk*3.2/sin(20)
solve for µk
µk=0.35

j