What Is the Correct Tension in Each Wire Holding Up the Light Fixture?

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The discussion centers on calculating the tension in two wires supporting a light fixture that exerts an 80N force at a 40-degree angle with the ceiling. The initial approach involved using trigonometry to find the hypotenuse, resulting in a tension value of 124.5N, which was incorrect according to the software used. The correct method involves resolving the forces perpendicular to the strings, leading to the equation 2Tsin(40) = 80, which indicates that the tension in each wire is actually 40N. The user confirmed that dividing the initial hypotenuse value by two provided the correct answer. The thread highlights the importance of correctly resolving forces in tension calculations.
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There are two wires connected to a ceiling with a light fixture hanging at their ends. The light fixture exerts a force of 80N, while the wires make a 40 degree angle with the ceiling. What is the tension in the two strings? The diagram roughly looks like this:

---------------
- 40 40 -
- -
- -
-
-
80N

I assumed that this was a simple trigonometry problem and set about solving it like so:
{a} I assumed that since the object was not moving downward, there had to be an 80N force exterted upward. Hence, I split the large triangle into two parts using a positive 80N force, making a 90 degree angle with the ceiling, and a 50 degree angle at the base of the larger triangle.
{b} From there I used trigonometry:
cos(50) = 80N/Hyp.
Hyp. = 80N/cos(50)
Hyp. = 124.5N

Yet, the software (Webassign.com) is telling me that the tension is not 124.5N. What am I doing wrong?

P.S.- I also tried assuming that there is not an 80N positive force exerted upward, and thereby tried isolating each X and Y vector for each string seperately. I still got the same answer of 124.5N.
 
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If they want the value for T in each string, you need to divide that value by 2. Resolve the forces perpendicular to the string and you get 2Tsin 40 = 80.
 
I thank you kindly, dividing 124.5N by two did work, and I appreciate your explanation as well. :smile:
 
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