Static equilibrium question

  • #1
A beam with negligible mass is balanced by two external forces at R1 = 1.5 meters and R2 = 6.5 meters. If F1 = 10 N, what is F2.

i got this:

(10)(1.5) + F2(6.5) = 0

so F2 = 2.31 N

but the second part i dont get:

If the beam actually has a weight of 3 N, what would F2 be now???
 

Answers and Replies

  • #2
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,160
504
A beam with negligible mass is balanced by two external forces at R1 = 1.5 meters and R2 = 6.5 meters. If F1 = 10 N, what is F2.

i got this:

(10)(1.5) + F2(6.5) = 0

so F2 = 2.31 N

but the second part i dont get:

If the beam actually has a weight of 3 N, what would F2 be now???
Well, your first equation in Part1 should read
10(1.5) - F2(6.5) = 0
F2 = 2.31N
You've got to watch your plus and minus signs, one moment is clockwise, the other is counterclockwise.
For Part 2, the 3N weight of the beam acts at its c.m. (or c.g.), that is, since the beam is 8m long, at 4m from one end. Try it again to solve for F2, watching your plus and minus signs. Remmber also the pivot point is at 1.5m.
 

Related Threads on Static equilibrium question

  • Last Post
Replies
14
Views
8K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
4
Views
487
  • Last Post
Replies
11
Views
7K
  • Last Post
Replies
3
Views
543
  • Last Post
Replies
11
Views
2K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
1
Views
983
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
18
Views
920
Top