- #1
jono240
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Homework Statement
This should be an easy one. Please tell me what I am missing.
A man is pushing a 75 kg crate at constant
velocity a distance of 12 m across a warehouse.
He is pushing with a force of 225 N at an angle
of 15° down from the horizontal. The coefficient
of friction between the crate and the floor is
0.24. How much work did the man do on the
crate?
Given - m=75kg, Δd=12m, Fa=225N [15° down from hor], μ=.24
Homework Equations
Ffriction = μ*Fn
W = F*Δd*cosθ
The Attempt at a Solution
First attempt
Ffriction = 176.4N
So
W = F*Δd*cosθ
W = (225 - 176.4)*12*cos15
W = 563.33N/m (wrong answer)
Second attempt
W = F*Δd*cosθ
W = 225*12*cos15
W = 2608N/m
W = F*Δd*cosθ
W = 176.4*12*cos180
W = -2116.8N/m
W = 2608 - 2116.8
W = 491.2N/m (wrong answer)
I've tried so many combinations I can't seem to figure it out. The answer is 320N/m btw
Please tell me what I am doing wrong