Work:kinetic frictional force

[shawonna23]

A 280 N force is pulling an 80.0 kg refrigerator across a horizontal surface. The force acts at an angle of 18.0° above the surface. The coefficient of kinetic friction is 0.200, and the refrigerator moves a distance of 6.00 m.
(a) Find the work done by the pulling force.
1.60*10^3 J
(b) Find the work done by the kinetic frictional force.
J

I have the answer for part a, but i keep getting the wrong answer for part b. Can someone please help me solve this problem?

[stunner5000pt]

A 280 N force is pulling an 80.0 kg refrigerator across a horizontal surface. The force acts at an angle of 18.0° above the surface. The coefficient of kinetic friction is 0.200, and the refrigerator moves a distance of 6.00 m.
(a) Find the work done by the pulling force.
1.60*10^3 J
(b) Find the work done by the kinetic frictional force.
J

I have the answer for part a, but i keep getting the wrong answer for part b. Can someone please help me solve this problem?

for the work done by frictional force


first of all Ff = coeff(Mu) times Normal force (N)

so N + 280sin18 - 80g = 0

Ff = Mu N

Work done by friction is Ff times distance