# Static equilibrium; pulley and inclined plane problem.

• J-dizzal
In summary, the conversation discusses finding the weight of block B that will cause the system to be in equilibrium, neglecting friction and making other assumptions. The equations used are ΣF=0 and the conversation includes attempts at solving the problem, including converting between English and standard units. The final conclusion is that the tension T/2 is the correct answer.
J-dizzal

## Homework Statement

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

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]

You should check the Wb is Tb or ___ ?

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)

It seems correct to me.

Thyphon said:
It seems correct to me.
Yea, but I am still missing something, its not the correct answer.

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

Thyphon said:
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

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
Thyphon said:
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.

Is it okay now ?

Thyphon said:
Is it okay now ?
yea its correct now. thanks

Why is the tension T/2?

## What is static equilibrium?

Static equilibrium is a state in which an object is at rest and the net force acting on it is equal to zero. This means that the object's acceleration is zero and there is no change in its motion.

## How is static equilibrium related to pulley and inclined plane problems?

In pulley and inclined plane problems, the goal is to find the point where the net force is equal to zero, which indicates that the system is in static equilibrium. This allows us to solve for unknown forces or tensions in the system.

## What is a pulley?

A pulley is a simple machine consisting of a grooved wheel and a rope or cable that runs along the groove. It is used to change the direction of a force and can be either fixed or movable.

## What is an inclined plane?

An inclined plane is a flat surface that is sloped at an angle. It is used to reduce the amount of force needed to lift an object by increasing the distance over which the force is applied.

## How do you solve pulley and inclined plane problems?

To solve pulley and inclined plane problems, you must first draw a free body diagram to identify all the forces acting on the system. Then, use Newton's laws of motion to set up equations and solve for unknown forces or tensions. Finally, check for static equilibrium by ensuring that the net force is equal to zero.

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