A 76.5 kg cross-country skier skiing on unwaxed skis along dry snow at a constant speed of 4.00 m/s experiences a force of friction of -60.0 N.  What is the coefficient of friction between unwaxed skis and dry snow?
a. 0.08
b. 0.78
c. 1.28
d. 12.5



Answer :

AL2006
The force of friction = (weight) x (coefficient of friction)

Skier's weight = (mass) x (gravity) = (76.5) x (9.8) = 749.7 N

Force of friction = (749.7) x (coefficient of friction) = 60.0 N

Coefficient of friction = 60 / 749.7 = 0.08  (rounded)

Choice-'A' is the closest choice offered.