A 10kg mass is suspended as shown:

Question

i.gyazo[dotcom]/47dc49d5ec1eebe950472dba5f692e70.png

(remove the brackets)

What is the tension in the cord between points A and B? What is the tension in all of the cords?

Thanks for the help, I just can't figure it out...

Answer 1

figure at
http://i.gyazo.com/47dc49d5ec1eebe950472dba5f692e70.png

I will only do the right half (symmetry)
5 kg down on the right half
5 kg * 9.81 = 49 Newtons

so
tension below B: call it TL
TL cos 30 = 49
so
TL = 56.6 N
so component of TL to the left at B
TL left = 56.6sin 30 = 29.3 left

now the upper tension
call it TU
TU cos 45 = 49
so
TU = 69.3 N

so component of TU right at B
TUright = 69.3 sin 45 = 49 of course

NOW we have it
T + TL left = TU right = 49
T = 49 - 29.3
T = 19.7 Newtons

Answer 2

Thank you so much