A 100 kg crate slides down a ramp, starting from rest. The ramp is inclined at an angle of 21.9 degrees with respect to the horizontal and has a height of 1.37 m. The coefficient of kinetic friction...

Extracted text: A 100 kg crate slides down a ramp, starting from rest. The ramp is inclined at an angle of 21.9 degrees with respect to the horizontal and has a height of 1.37 m. The coefficient of kinetic friction between the crate and the ramp is us = 0.30. What is the work done on the crate (in Joules) by the normal force?