Engineering Statics Question

  • Thread starter d0ntg3t1t
  • Start date
  • #1
1
0

Homework Statement



http://imgur.com/a/FyekZ
I took the liberty of uploading everything. The first picture is the question, while the other two is my attempt at answering it in two parts. What I do not understand is what I did wrong or where I went wrong.
I also would like to know why, unlike many other questions from the text, this question does not specify in which direction the resultant force is directed. Is the question wrong, or am I supposed to go about this in a different manner?

EDIT: If you cannot see the full image, please click the gear icon (top right of each image - gear appears when you have the mouse over the image) and select view full resolution.

Homework Equations



See above.

The Attempt at a Solution



Please see above.
 

Answers and Replies

  • #2
CWatters
Science Advisor
Homework Helper
Gold Member
10,533
2,298
Deleted.
 
Last edited:
  • #3
CWatters
Science Advisor
Homework Helper
Gold Member
10,533
2,298
Ok so there appears to be too many unknowns unless you assume the resulting force is to be in the "u" direction.
 
  • #4
CWatters
Science Advisor
Homework Helper
Gold Member
10,533
2,298
I think you may have made an error in the calc for Fry. Did you forgot to divide by Sin(28)?
 
  • #5
CWatters
Science Advisor
Homework Helper
Gold Member
10,533
2,298
Actually it looks like you can calculate the angle of the resultant. Call that β then..

In x..

FR*Cos(β) = F1*Cos(θ) - F2*3/5 + F3*Cos(45)
so
F1*Cos(θ) = FR*Cos(β) + F2*3/5 - F3*Cos(45) ............(1)

In y..

FR*Sin(β) = F1*Sin(θ) + F2*4/5 - F3*Sin(45)
so
F1*Sin(θ) = FR*Sin(β) - F2*4/5 + F3*Sin(45)................(2)


Knowns F2, F3, FR, θ
Unknowns F1 and β

We have two equations and two unknowns.
 

Related Threads on Engineering Statics Question

  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
5
Views
2K
Replies
4
Views
957
Replies
6
Views
1K
Replies
5
Views
1K
Replies
3
Views
4K
  • Last Post
Replies
9
Views
2K
  • Last Post
Replies
1
Views
1K
Top