Given the diagram, what is the tension in each string?

[laladude]

Homework Statement

Given this diagram and the masses involved, what is the Tension in each string. All masses are 1kg.

Diagram provided

Sorry, the angle for T2 is 10°

Homework Equations

The Attempt at a Solution

I really don't know where to start.

 

[Redbelly98]

For each mass, draw a force diagram.

Then use ∑F_x=ma_x and ∑F_y=ma_y. (And you should know what a_x and a_y are )

 

[laladude]

For each mass, draw a force diagram.

Then use ∑F_x=ma_x and ∑F_y=ma_y. (And you should know what a_x and a_y are )

okay, so for T1 and T2..

x-dir would be ∑Fx = - T1 cos30 + T2 cos10 = 0

y-dir would be ∑Fy = T1 cos30 + T2 cos10 + -mg = 0

Then solve for T1 = T2 cos10/cos30 = 0

Plug into y-dir eq. (T2 cos10/cos30) cos30 + T2 cos10 = mg

T2 = mg/1.97 which is 4.97.

Then plug T2 to T1. Correct?

Now I am uncertain about T3 and T4..

 

[Redbelly98]

okay, so for T1 and T2..

x-dir would be ∑Fx = - T1 cos30 + T2 cos10 = 0

Yes, good.

y-dir would be ∑Fy = T1 cos30 + T2 cos10 + -mg = 0

Almost -- for the y-dir, we use sin instead of cos.

Then solve for T1 = T2 cos10/cos30 = 0

Except for the "=0" part, that is correct.

Plug into y-dir eq. (T2 cos10/cos30) cos30 + T2 cos10 = mg

Yes, except that there should be some sin's in there because of what I said before about the y-direction forces.

T2 = mg/1.97 which is 4.97.

Then plug T2 to T1. Correct?

Yes, that is the idea.

Now I am uncertain about T3 and T4..

Have a look at the forces acting on Mass #3.