Question

A 65kg sled is pulled along a level surface at constant velocity by a constant force of 200N at an angle of 30°. What is the coefficient of friction between the sled and the surface?

Answer 1

N = normal force on the sled

f = frictional force on the sled

m = mass of the sled = 65 kg

Along the horizontal direction , force equation is given as

200 Cos30 - f = 0

f = 200 Cos30

f = 173.2 N

Along the vertical direction , force equation is given as

N + 200 Sin30 = mg

N + 200 Sin30 = 65 x 9.8

N = 537 N

Coefficient of friction is given as

μ = f/N

inserting the values

μ = 173.2/537

μ = 0.322