Static equilibrium with Youn modulus

In summary, the problem involves a 103 kg log hanging from two steel wires, A and B, with different initial lengths. The log is now horizontal, and the goal is to find the magnitudes of the forces on it from each wire. To approach this problem, we can use the equation for Young's Modulus to calculate the tension in each wire, and then use the fact that the log is horizontal to create a relationship between the two tensions. We can also use the weight of the log to create a second relationship between the two unknown forces.
  • #1
Toranc3
189
0

Homework Statement


In Figure, a 103 kg uniform log hangs by two steel wires, A and B, both of radiuses 1.20 mm. Initially, wire A was 2.50 m long and 2.00 mm shorter than wire B. The log is now horizontal. What are the magnitudes of the forces on it from Wire A, and Wire B?
Ysteel= 2.00*10^(11) Pa[url=http://www.freeimagehosting.net/rsgtl][PLAIN]http://www.freeimagehosting.net/t/rsgtl.jpg[/url][/PLAIN]

Homework Equations



Young Modulus = (F(perpendicular)/Area)/(ΔL/L(initial))

The Attempt at a Solution


This is static equilibrium
so

Summation of Forces:
F: Ta-Tb-Wb =0

Not sure where to take it from here. Can somebody give me a direction?

Homework Statement


Homework Equations


The Attempt at a Solution

 
Last edited:
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  • #2
For a wire under tension, what is the formula for the amount it stretches?
 
  • #3
SteamKing said:
For a wire under tension, what is the formula for the amount it stretches?

Would it be tensile strain?

Tensile strain=ΔL/L
 
  • #4
Yeah, but what is the formula for calculating delta L?
 
  • #5
SteamKing said:
Yeah, but what is the formula for calculating delta L?

Lfinal minus Linitial right
 
  • #6
Read your problem carefully. You have two wires, one of which is slightly shorter than the other when there is no load (no tension) applied. After the log is suspended, it is perfectly horizontal, suggesting that both wires under tension are now the same length. How would you use the equation for Young's Modulus to calculate the tension in each wire?
 
  • #7
If wire A had a length of L0A = 2.5 meters before it was loaded, and wire A had a length 2 mm shorter than wire B before it was loaded, what was the length L0B of wire B before it was loaded?

If FA is the force in wire A, and FB is the force in wire B, what is the equation for the strain εA and εB in each of these wires in terms of Young's modulus?

From this, and knowing the unloaded lengths of the two wires, write an equation for the loaded lengths of the two wires LA and LB. Since the log is horizontal, what does this tell you about the relationship between LA and LB? This should give you a single relationship between FA and FB.

How are FA and FB related to the weight of the log? This should give you your second relationship between the unknowns FA and FB.
 

Related to Static equilibrium with Youn modulus

1. What is static equilibrium?

Static equilibrium is a state in which all forces acting on an object are balanced, resulting in no net force and no movement of the object.

2. What is Young's modulus?

Young's modulus, also known as the elastic modulus, is a measure of a material's stiffness or resistance to deformation under an applied force. It is defined as the ratio of stress (force per unit area) to strain (change in length per unit length) in a material.

3. How is static equilibrium related to Young's modulus?

In order for an object to be in static equilibrium, the forces acting on it must be balanced. This includes any external forces as well as internal forces within the material. Young's modulus is a measure of the internal forces within a material, and it is used to determine how much a material will deform under a given amount of stress. When an object is in static equilibrium, the material is not deforming, meaning the internal forces are balanced.

4. What factors can affect static equilibrium with Young's modulus?

The main factor that affects static equilibrium with Young's modulus is the material's stiffness, which is represented by its Young's modulus value. Other factors that can affect static equilibrium include the shape and size of the object, the magnitude and direction of applied forces, and the support conditions of the object.

5. How is Young's modulus calculated?

You can calculate Young's modulus by dividing the stress by the strain. This can be done using the equation E = σ/ε, where E is the Young's modulus, σ is the stress, and ε is the strain. Young's modulus is typically expressed in units of pressure, such as Pascals (Pa) or pounds per square inch (psi).

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