• Support PF! Buy your school textbooks, materials and every day products Here!

Moment with two unknown forces

  • #1
Member advised to use the homework template for posts in the homework sections of PF.
Ok here goes. It's been a long time since i've done anything like this and i just cant remember what to do.

I'e got a beam 167.5mm long. It is supported at 24.5mm along the beam.

6600kgf acts at one end of the beam.

F1 acts at 128.5mm along the beam. F2 acts at 167.5mm along the beam.

F1 and F2 are different and the beam is balanced.

How do i calculate F1 and F2?

Cheers
 

Answers and Replies

  • #2
CWatters
Science Advisor
Homework Helper
Gold Member
10,529
2,295
You posted in the homework section so should use the template.

Perhaps start with a diagram?

It's a static problem so the net force is zero and the net torque about any point is zero.
 
  • #3
It's a static problem so the net force is zero and the net torque about any point is zero.[/QUOTE]

I agree with static problem thing.
But how can we get F1 and F2.
 
  • #4
jbriggs444
Science Advisor
Homework Helper
2019 Award
8,775
3,532
I agree with static problem thing.
But how can we get F1 and F2.
You have to show some work before we are allowed to help you.
 
  • #5
20,230
4,264
It's a static problem so the net force is zero and the net torque about any point is zero.
I agree with static problem thing.
But how can we get F1 and F2.[/QUOTE]
Let's see your force- and moment balance equations.
 
  • #6
CWatters
Science Advisor
Homework Helper
Gold Member
10,529
2,295
As there are two unknowns (F1 and F2) you will need two simultaneous equations. See my post #2 for a hint.
 
  • #7
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,156
502
Looks like 3 unknowns. The single support reaction is an unknown. There is no specific solution. If the problem is stated correctly.
 
Last edited:
  • #8
CWatters
Science Advisor
Homework Helper
Gold Member
10,529
2,295
On reading the OP again I think I agree.
 
  • #9
gneill
Mentor
20,795
2,773
Looks like 3 unknowns. The single support reaction is an unknown. There is no specific solution. If the problem is stated correctly.
It's worse than that. The problem doesn't state how the forces F1 and F2 are acting: Are they both acting upwards? One up one down? Something else? Which end of the beam is the 6600 kgf acting?

I'm very tempted to simply delete the thread and ask the OP to start over with a full disclosure of the original question in its original form (and to use the template, of course).
 
  • #10
CWatters
Science Advisor
Homework Helper
Gold Member
10,529
2,295
I wouldn't delete it. I think better to close it until the OP responds to your PM.
 

Related Threads on Moment with two unknown forces

Replies
4
Views
12K
  • Last Post
Replies
3
Views
3K
Replies
3
Views
8K
  • Last Post
Replies
4
Views
2K
Replies
1
Views
1K
Replies
6
Views
2K
  • Last Post
Replies
2
Views
7K
Replies
6
Views
4K
  • Last Post
Replies
8
Views
2K
Replies
6
Views
5K
Top