Calculating Work Done by a Force on a Moving Object

AI Thread Summary
The discussion centers on calculating the work done by a force on a block moving from -3.00 cm to 5.00 cm, using the formula W = F*S*cos(theta). Initially, the user calculated work as W = -260J, but realized a mistake in defining displacement. After correcting the displacement to 8 cm, the user recalculated the work as W = 680J. Participants emphasized the importance of consistent units and proper calculations in physics problems. The user expressed frustration over their initial errors but planned to revisit the problem later.
Abarak
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Homework Statement


Find the work W done on the block by the force of magnitude F = 85.0N as the block moves from xi = -3.00cm to xf = 5.00cm.

Homework Equations


W = F*S*cos(theta)

The Attempt at a Solution


W = (85.0N)(-3cm-5cm)*1
W = -260J

Am I missing something?
 
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The definition of displacement.
 
And a consistent set of units
 
Let me try this again...

W = (85.0N)(3cm+5cm)*1
W = 680J

(3cm + 5cm) because the block is moving from -3cm to 0 and from 0 to 5cm. This gives us a grand total of 8cm the block was moved. Sorry for the rather rudimentary question.
 
Abarak said:
W = (85.0N)(-3cm-5cm)*1
W = -260J

Am I missing something?

a calculator??
and check the units
Newton * meter = joule
 
God, that was terrible. I'm going to stop right now and start again tomorrow. Sorry for the waste of time.
 
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