Static equilibrium; pulley and inclined plane problem.

[J-dizzal]

Homework Statement

What weight WB will cause the system to be in equilibrium? Neglect all friction, and state any other assumptions.

Homework Equations

ΣF=0

The Attempt at a Solution

I can't figure out what I am doing wrong with these pully problems, I tried putting in resultant forces at pully A, but that just added another variable.[/B]

 

[Thyphon]

You should check the Wb is Tb or ___ ?

 

[J-dizzal]

I did a redo of the tensions this time starting from A going to B, I am still missing something though. solving for weight at B i got 8.72lb (on the right side of my paper)

 

[Thyphon]

It seems correct to me.

 

[J-dizzal]

It seems correct to me.

Yea, but I am still missing something, its not the correct answer.

 

[Thyphon]

Oh, find the F again you will see the wrong :) 79,5 N or kg ?

 

[J-dizzal]

Oh, find the F again you will see the wrong :) 79,5 N or kg ?

If the weight of block A is 175 lb that is equal to 79.5N

 

[J-dizzal]

ok i got, my mistake was trying to convert from english to standard, i should of just left it in english. thanks thypon.

 

[Thyphon]

No, 1lb is equal to 0,453 kg, so 175lb =79,27 kg
N means kg*m/(s^2)

 

[J-dizzal]

No, 1lb is equal to 0,453 kg, so 175lb =79,27 kg
N means kg*m/(s^2)

i got confused because 175 lb of weight = 175 lb mass.

 

[Thyphon]

Is it okay now ?

 

[J-dizzal]

Is it okay now ?

yea its correct now. thanks

 

[markansu97]

Why is the tension T/2?