Question

an 7.8kg crate is pulled 4.6m up a 30 degree incline by a rope angled 17 degrees above the incline. the tension in the rope is 140N and the crate's coefficient of kinetic friction on the incline is 0.24. How much work is done by tension, by gravity, and by the normal force? What is the increase in thermal energy of the crate and incline?

Answer 1

Answer 2

The component of weight in line with the ramp is W_r=7.8 * g * sin30 .
The component of the rope force in line with the ramp is F_r= 140*cos17
The friction force resisting motion is F_f=7.8 * g * 0.24 *cos30
a)
Work done by tension = F_r*4.6=615.8J
Work done by gravity = W_r*4.6=175.9 J
Work done by normal force = 7.8 * g * cos30 * 4.6 *sin30= 152.4 J
b)
= F_f*4.6 = 73.15 J