Starting from rest, a mass m = 15 kg is pulled along a horizontal floor with NO

Question

Starting from rest, a mass m = 15 kg is pulled along a horizontal floor with NO friction for a distance d =6.9 m. Then the mass is pulled up an incline that makes an angle ? = 28° with the horizontal and has a coefficient of kinetic friction ?k = 0.37. The entire time the massless rope used to pull the block is pulled parallel to the incline at an angle of ? = 28° (thus on the incline it is parallel to the surface) and has a tension T =49 N.

I've already found the answers for the first two questions, which are the work done my tension which is 298.5 and the speed right before the incline which is about 6.3. I have a few more questions left that I can't figure out.

C) What is the work done by friction after the block has traveled a distance x = 2.6 m up the incline? (Where x is measured along the incline.)

D) What is the work done by gravity after the block has traveled a distance x = 2.6 m up the incline? (Where x is measured along the incline.)

Explanation / Answer

c)

here

normal force Fn = m * g * cos( 28deg)

W = 2.6 * 0.37 * 15 * 9.8 * cos( 28deg)

W = 124.8 J

d)

here also

W = 2.6 * 15 * 9.8 * sin(28deg)

W = 179.43 J

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