# Does either rope break?

1. Oct 8, 2007

### circuscircus

1. The problem statement, all variables and given/known data
A 1000kb steel beam is supported by two ropes. Each rope as a maximum sustained tension of 6000N. Does either rope break? If so, which one(s)?

http://img101.imageshack.us/img101/3930/diagramgm2.jpg [Broken]

2. Relevant equations
Tension = M cos/sin theta
(in this case it is cos)

3. The attempt at a solution
Rope1 = 6000cos20 = 5638N
Rope2 = 6000cos30 = 5196N
W=1000*9.8 = 9800N / 2 = 4900N so no It does not break, but the answer says rope 1 breaks first and then rope 2

Last edited by a moderator: May 3, 2017
2. Oct 8, 2007

### bob1182006

the equations you used are wrong. as well as the angles you used.

you need to use F=ma for the x and y components and you will get 2 equations of 2 variables which you can solve as a matrix or plugging it into your calculator.

for the x-component the tensions cancel out right?
and for the y-component the tensions will equal to the weight of the beam?