Question

A 2.30 102 N force is pulling an 80.0 kg refrigerator across a horizontal surface. The force acts at an angle of 21.0° above the surface. The coefficient of kinetic friction is 0.200, and the refrigerator moves a distance of 7.00 m.
(a) Find the work done by the pulling force.
(b) Find the work done by the kinetic frictional force.

Answer 1

work done= force.distance where the dot is the cosine of the angle between.

= 2.3E2*7 * cosine 21
work done by friction:
= forcefriction*distance=mu(fn)*distance
where fnormal= mg-2.3E2Sin21

Answer 2

(a) 2.30*10^2*cos21*7.00 m = ___ J
(b) 80.0*g*(0.200)*7.00 = (-) ____ J
The friction force actually does negative work.

Answer 3

The answer is wrong. What did u get?

Answer 4

My part b is wrong because I neglected the upward force provided by the rope, which reduces friction. Use BobPursely's equation

Answer 5

you use the mg-(2.3E2*cos21)for fnormal...bobpursley you really should check your work before...