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Find the tension in the two wires

  • Thread starter kp87
  • Start date
  • #1
7
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Homework Statement


Find the tension in the two wires supporting the 36 kg traffic light shown in Fig. 12-57. (Assume that 1 = 52° and 2 = 38°.)

http://img15.imgspot.com/u/07/77/15/952alt.gif [Broken]

Homework Equations


-T1cos(52)+T2cos(38)=m*g
T1sin(52)+T2sin(38)=0


The Attempt at a Solution



so I found T1=-T2sin(38)/sin(52)
and plugged into the first equation and got
[sin(38)*cos(52)/sin(52)+cos(38)]*T2=353.16
and got T2 = 278N
and T1=217N

but when I put it into the webassign it is wrong...
so what am I doing wrong?
 
Last edited by a moderator:

Answers and Replies

  • #2
radou
Homework Helper
3,115
6
It would be useful if you presented the figure somehow.

You may want to check your trig, although I can't tell for sure.
 
  • #3
960
0
i think the sins and cosines are reversed. The vertical weight mg is opposed by the sines of the respective tensions.
 
  • #4
radou
Homework Helper
3,115
6
denverdoc is right. Just "swap" m*g and 0.
 
  • #5
7
0
k thx a lot got it :)
 

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