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

Principle of Moments

  • Thread starter Marcus27
  • Start date
  • #1
11
1

Homework Statement


Calculate the tension in the rope, T, in the diagram below: http://imageshack.com/a/img905/2848/yMC01l.png [Broken]

Homework Equations




The Attempt at a Solution


The 'beam' is a stable structure, thus the resultant forces be equal that are acting upon the beam. So,
I calculated the the Torque from the mass as being 150N * 0.6m + 100N * 0.3m = 110 Nm, setting this equal to the Torque generated by the 'force line' from the rope, T*1.2m = 110Nm, thus T rounded to the nearest Newton is = 92N. I Felt fairly confident with this until my textbook said the tension in the rope is = to 100N. Can anybody clear this up for me and explain where I went wrong, Thanks!.
 
Last edited by a moderator:

Answers and Replies

  • #2
Bystander
Science Advisor
Homework Helper
Gold Member
5,173
1,173
150N * 0.6m + 100N * 0.3m = 110 Nm
Check your arithmetic, that's "the usual suspect."
 
  • #3
11
1
Ah, thank you. I did not spot that mistake, sorry for wasting your time. Not a great first post on my part o:)
 
  • #4
Bystander
Science Advisor
Homework Helper
Gold Member
5,173
1,173
Do not let it ruin your day --- we've all been there.
 

Related Threads on Principle of Moments

  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
2
Views
1K
Replies
4
Views
5K
  • Last Post
Replies
1
Views
741
  • Last Post
Replies
2
Views
3K
Replies
10
Views
6K
Replies
2
Views
599
Replies
2
Views
5K
Replies
4
Views
12K
  • Last Post
Replies
1
Views
1K
Top