Question

A 6,00 kg box is pulled 8,00 m up a rough incline at an angle of 30,0° by a force of 50,0 N parallel to

the incline. The coefficient of kinetic friction is 0,100. The work done against friction is...? (Give your
answer to 3 significant figures.)

Answer 1

W= f.d cos θ

W = μk.N.d cos θ

W = μk.m.g.d cos θ

W = 0.1 x 6 x 10 x 8 sin 30° x cos 30°

W = 20.8 J

Answer 2

M=1 kg θ=30o

F=10 N μ=0.1

Distance d=10 m (on inclined plane)

(a) Work done against gravity =mgh

sin30o=10h​

h=10sin30o=10×21​=5 m

∴WD against gravity =1×10×5=50 j

Step-by-step explanation: