Question
provious 11 of 14 ne Problem 7.07 Part B A factory worker moves a 30.0 kg crate a distance of How much work is done on the crate by the worker's push? 5.40 m along a level floor at constant velocity by pushing horizontally on it. The coefficient of kinetic friction between the crate and the floor is 0.250 Submit Incorrect; Try Again; 16 attempts remaining Part C How much work is done on the crate by friction? friction = Submit My Answers Give Up Incorrect; Try Again; 18 attempts remaining Part D How much work is done by the normal force?
Explanation / Answer
Perpendicular to the incline,
N - m g = 0
N = m g
f = uk m g
along the incline,
F - f = 0
F = uk m g
(B) W = F d
= (uk m g ) (d)
= 0.250 x 30 x 9.8 x 5.40
= 396.9 J
(c) Work done by friction = - uk m g d
= - 396.9 J