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bakakun028
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Homework Statement
A loaded grocery cart is rolling across a parking lot in a strong wind. You apply a constant force f = (30N)i - (40N)j to the cart as it undergoes a displacement s = (-9.0m)i - (3.0m)j
How much work does the force you apply do on the grocery cart?
Homework Equations
The Attempt at a Solution
I was assuming all I needed to do was do F*d for the i unit vector and j unit vector like so:
W = (F*d)i + (F*d)j = (30*-9)i + (-40*-3)j = (-270J)i + (120J)j
But according to the answer book, the final work has no unit vectors involved and it is the sum of those two calculated works.
-270J + 120J = -150J
How come the unit vectors are not included in the answer? Also, how come we can simply sum up the x and y W's and works like that? I know it has something to do with work being a scalar...