Shouldn't this force have a horizontal component, too?

[Femme_physics]

In the solution manual (which I never trust) the tension vector of the rope that emerges from point A only has a vertical component when calculating the sum of all moments on joint C. I disagree with the solution manual, since this vector also has a horizontal component, and if you calculate its arm it's simply 20sin(20). Sure, small arm and weak vector compared to the vertical one, but still a vector. Am I right?


http://img580.imageshack.us/img580/1845/horiz.jpg

 

[AlephZero]

Yup, I think you are right.

If you call the components of tension in the rope Tx and Ty, you have two equations:

1. Take moments about C.
2. The resultant of Tx and Ty acts along the direction of the rope (so you need to work out the angle of the rope to the vertical, from the geometry).

 

[Femme_physics]

I did using law of cosines than law of sines, it's 62.4 :) Thanks

*snaps finger* another mistake found!

That's practically the 4th mistake, I think.

I'm seriously going to author a correction manual to the solution manual, I will credit physicsforums.com for helping me. I doubt I'll publish it officially, but it will at least be in my college's library and have my professor's stamp of approval.."at least" :)