# Homework Help: Calculating Work done by a force

1. Apr 26, 2010

### Eikcuhc

[/COLOR]1. The problem statement, all variables and given/known data
[URL]http://einstein.math.fsu.edu:9080/testbanks/wiley/math/1114ptF08/cch/images/qu.215.9.question.gif[/URL]

2. Relevant equations
I know that
W = Fd where here it is
W = F * $${\rightarrow}{\}$$AB

Also, that

(im sorry, this looks really ugly)
$$\stackrel{v\rightarrow}{}$$ = ||v||(cos$$\alpha$$$$\stackrel{i\rightarrow}{}$$+sin$$\alpha$$$$\stackrel{j\rightarrow}{}$$)
||v|| = sqrt(a2+b2)

3. The attempt at a solution
I get stuck fairly quickly on this problem, my professor never went on it in class.

using the second equation, I get to the point of

v = (sqrt13)(cos+sin)

I am not sure what goes into the cos and sin portion of the problem, I am assuming it has something to do with the coordinates it gives, but other than that, I have no idea.

Last edited by a moderator: Apr 25, 2017
2. Apr 26, 2010

### rock.freak667

Ok, so your force is 5lbs in the direction of 3i+2j, so what is your force vector F?

The displacement is from (0,0) to (0,4), what is you displacement vector d equal to?