Answer:
a) The work done by pulling force, W = 1804.21 joules
b) The work done by the kinetic frictional force is, w = 1332.8 J
Explanation:
Given,
The pulling force, Fₐ = 2.4 x 10² newton
The mass of the refrigerator, m = 85 Kg
The angle of pulling force acting to the surface, ∅ = 20°
The coefficient of kinetic friction is, μₓ = 0.200
The distance covered by the refrigerator, s = 8 m
The force acting in the direction parallel to the surface is given by
F = Fₐ cos∅
∴ F = 2.4 x 10² x cos 20°
=225.53 N
The work done by the pulling force is given by
W = F · S
= 225.53 N x 8 m
= 1804.21 joules
The work done by the pulling force, W = 1804.21 joules
The kinetic friction force is given by the formula
Fₓ = μₓ · η
Where
μₓ - coeficient of kinetic frictoin
η - Normal force, (mg)
∴ Fₓ = 0.200 x 85 x 9.8
= 166.6 N
The work done by the kinetic frictional force is given by
w = Fₓ · S
= 166.6 N x 8 m
= 1332.8 J
Hence, the work done by the kinetic frictional force is, w = 1332.8 J
