Question

I have a problem with this http://prntscr.com/24xad7

I feel like I'm not given enough information to solve it, but I am unsure, this is a new concept for me, can anyone explain it to me? Thanks!

Answer 1

I do know this, T1 and T2 together, equal the downward force on the mass of 30N. As for what this means at the intersection point of all 3, Im not sure.

To find T1 and T2 in component form, you do: forces going x (horz) and going y (vert)
Forces in (x-direction) = +T1cos(theta)+ (-)T2 cos(theta) =0

Tension in T1 has an "invisible line making the bottom of a triangle" going right,, as in the +x direction, so its +T1cos(theta)
Tension in T2 has an "invisible line making the bottom of a triangle" going left, as in the -x direction, so it is -T2cos(theta)

In the y-direction, the tension running "up the triangle" for T1 and "down the triangle twrds the mass" in T2 are summed up.
Forces in y: +T1sin(theta) + -T2sin(theta)=0
It equals 0, bc they both balance out.
The positive and negative are again because of the way the "invisible line" runs

Then as a 3rd equation,
The forces of T1 and T2 (both of their x and y parts), equal the weight of the block (30N).
So, T1 +T2 = 30N

You use the first 2 equations to isolate one tension, say T1.
Whatever that equals, you sub into the 3rd equation and can solve the T2.