# How to calculate the tension in a beam of a bridge?

What's negative?
Unless you identify what you are talking about and what sign convention you are using, "positive" and "negative" are just meaningless noises.
Sorry the torque due to T is negative.
I broke the space key on my keyboard so I am being a bit lazy with words.

jbriggs444
Homework Helper
Sorry the torque due to T is negative.
I broke the space key on my keyboard so I am being a bit lazy with words.
So you add a negative to a negative and get zero?

[Back in #18, you said that the torque due to FP was negative. Now you say that the torque due to T is also negative]

So you add a negative to a negative and get zero?

[Back in #18, you said that the torque due to FP was negative. Now you say that the torque due to T is also negative]
Sorry I got mixed up the torque due to the tension should be positive.

jbriggs444
Homework Helper
Sorry I got mixed up the torque due to the tension should be positive.
Ok. And since your convention is that positive is counter-clockwise, we are talking about compression. If T is the "tension" in that beam then T must be negative.

So, can you now solve for T?

Last edited:
Wimpalot
Ok. And since your convention is that positive is counter-clockwise, we are talking about compression. If T is the "tension" in that beam than T must be negative.

So, can you now solve for T?
Yeah just T = -FP*L/(L*sin(60)) which is correct according the site.

Thank you very much for all the help I really feel like I understand this now and can apply it all in the future so thank you very much.

jbriggs444