Question

3.59 X 102-N force is used to pull a 95.0-kg refrigerator across a horizontal surface. The force acts at an angle of 23.50 above the horizontal surface. The coefficient of kinetic friction is 0.289, and the refrigerator moves a distance of 12.3 m. (a) What is the work done by the pulling force? (b) What is the work done by the kinetic frictional force?

Answer 1

Answer:

a) W = 40.49 10² J  and b)  W₂ = - 3308.7 J

Explanation:

The equation for work is

      W = F. d

Bold indicates vectors, we can also write that equation with the modules

      W = F d cos θ

Where θ is the angle between force and displacement

a) Traction reinforcement work

     W = 3.59 10² 12.3 cos 23.5

     W = 40.49 10² J

b) frictional force work, we have to use Newton's second law to find the friction force

Y Axis

     N-W = 0

     N = W

The formula for friction force is

     fr = μ N

     fr = μ mg

     fr = 0.289  95.0  9.8

     fr = 269 N

The friction force opposes the movement, so that at an angle it is 180º

    W₂ = fr d cos T

    W₂ = 269 12.3 cos 180

    W₂ = - 3308.7 J