A factory worker pushes a 28.9 kg crate a distance of 4.0 m along a level floor at constant velocity by pushing downward at an angle of 28∘ below the horizontal. The coefficient of kinetic friction between the crate and floor is 0.26.
a) What magnitude of force must the worker apply to move the crate at constant velocity?
b) How much work is done on the crate by this force when the crate is pushed a distance of 4.0 m? Express your answer using two significant figures.
c) How much work is done on the crate by friction during this displacement? Express your answer using two significant figures.
d) How much work is done by the normal force?
e) How much work is done by gravity?
f) What is the total work done on the crate?