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Forces diagram question

  • Thread starter lektor
  • Start date
  • #1
56
0
with reference to the diagram, at what angle must the 800N force be applied in order that the resultant R of the two forces has a magnitude of 2000N.

We were instructed to use the i,j method.

So, the forces for Fi = 800sin(-) and Fj = 1400 + 800 cos(-) and the resultant is 2000N.

This is where i get stuck, a^2 + b^2 = c^2
so 2000^2 = (800 sin(-))^2 + (1400+800 cos(-))^2

any help would be great.
 

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Answers and Replies

  • #2
56
0
bump^

please help :p
 
  • #3
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
9,622
6
lektor said:
bump^

please help :p
We can't see the attachment yet...
 
  • #4
56
0
it is simply a diagram showing

|........./
|......./
|(-)./
|.../
|./

with the verticle line saying 1400N and the diagonal line saying 800N
 
  • #5
mukundpa
Homework Helper
524
3
It appears correct, expand

2000^2= 800^2 sin^2(@) + 1400^2 +2*1400*800*cos@ + 800^2*cos^2@

2000^2 - 800^2 - 1400^2 = 2*1400*800*cos@

solve for cos@


MP
 

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