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#1 If person #2 is applying a force of 200 N determine work of the kinetic friction force. Assume Person #1 has a mass of 70 kg. Assume person #1 is dragged over a distance of 5 m. #2 Determine the work done by Person #2 (applied force) on Person #1 if Person #1 is dragged over a distance of 5 m. Again, assume Person #1 is 70 kg. #3 Determine the net work done on Person #1 if Person #1 is dragged over a distance of 10 m.enter image description here

I am confused because I know that the normal force and the gravitational force do no work because they are perpendicular to the displacement. But I don't know how to answer question #1 because I feel like I need to know the value of the coefficient of kinetic energy in order to solve it and I was not given that.

Ellie
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1 Answers1

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Hint: The velocity along the surface is constant. That means that the acceleration is zero. From Newton's second principle, the sum of horizontal forces is zero. You have $200N\cos 30^\circ$ pulling, and you have $F_{friction}$ opposing the motion. The two forces must have the same magnitude.

Andrei
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