How much work is done by this pushing force in overcoming friction?

Question

An person is pushing hefty a carton of mass 33.3 kg at a point of 28 degrees from he flat at a steady speed. The plentifulness of pushing power approaches 222 N. The understudy moves this carton a good ways off of 12.3 meters.

a) How much work is done by this pushing force in overcoming friction?

b) The person gets the box vertically and places it on a rack 1.33 meters high. How much work did the person do?

c)If the person finished lifting the box in 2.55 seconds what was the power of the lift?

Answer 1

a. If there were no friction, the pusher would have to overcome a force due to gravity of 33.3 kg x 9.8 m/s² x sin28° or 153.2 N. The work done going up the slope is 153.2 n x 12.3 m = 1884 J. As the actual force needed was 222 N, the total work done was 222 N x 12.3m = 2730 J. The difference between 2730 J and 1884 J is the work done to overcome friction or 846 J.

b. The work necessary to lift the carton 1.33 m is 33.3 kg x 9.8 m/s² x 1.33 m = 434 J.

c. Power is the rate of work J/s, so 434 J/2.55 s = 170 watts.

As always, check the math and reasoning.