Calculating Work Done by a Force on a Moving Object

[Abarak]

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?

 

[neutrino]

The definition of displacement.

 

[mgb_phys]

And a consistent set of units

 

[Abarak]

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.

 

[ank_gl]

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

Am I missing something?

a calculator??
and check the units
Newton * meter = joule

 

[Abarak]

God, that was terrible. I'm going to stop right now and start again tomorrow. Sorry for the waste of time.