Thermal expansion bt. steel rule and vycor glass brick

In summary: You have to know the initial length and the temperature change, and the coefficient. Then use the equation that's appropriate for how the temperature change is expressed. You can convert from Celcius to Kelvin if you need to.In summary, to calculate the change in length of a steel rule and a Vycor glass brick at 80.00 C, use the linear coefficients of expansion for steel and glass, along with the initial length and the difference in temperature, to calculate the change in length for each material separately.
  • #1
mg1977
10
0

Homework Statement


A steel rule is calibrated for meauring lengths at 20.00 C. The rule is used to mesure the length of a Vycor glass brick; when both are at 20.00 C the length is 25.00cm. What is the length of both the rule and the brick when at 80.00 C


Homework Equations


coef of glass a=.75 *10^-6K
coef of steel a=12*10^-6 K


The Attempt at a Solution

.75*10^-6K *60.0 (the diff of Temp)*25.0 (L inital)
after this I am confused
 
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  • #2
mg1977 said:

Homework Statement


A steel rule is calibrated for meauring lengths at 20.00 C. The rule is used to mesure the length of a Vycor glass brick; when both are at 20.00 C the length is 25.00cm. What is the length of both the rule and the brick when at 80.00 C


Homework Equations


coef of glass a=.75 *10^-6K
coef of steel a=12*10^-6 K


The Attempt at a Solution

.75*10^-6K *60.0 (the diff of Temp)*25.0 (L inital)
after this I am confused

I don't think you've listed the coefficient equations quite right. The "K" that you've put at the end of each -- is that meant to signify that the units are 1/Kelvin? Because linear coefficients of expansion are in units of meters per meter Kelvin (m/m*K), or meters per meter Celcius (m/m*C).

http://en.wikipedia.org/wiki/Thermal_expansion

And to your question, how do you apply a linear coefficient of expansion to calculate the change in length?
 
  • #3
I was using the books list. So should I still use the Coeffient for glass even though the problem says to assume that the glass doesn't expand in this problem.What is the proper way to set up my formula and coeff ? Can you show me another way?
 
  • #4
mg1977 said:
I was using the books list. So should I still use the Coeffient for glass even though the problem says to assume that the glass doesn't expand in this problem.What is the proper way to set up my formula and coeff ? Can you show me another way?

It doesn't say anywhere in your original post that the glass brick does not expand. Have you posted the full text of the question?

And as for how to use the coefficients to calculate the change in length, surely your book has examples on how to do it...?
 
  • #5
a is linear coeffient and B is volume expansion coeffiecient.
 
  • #6
No, there aren't many examples in the book on this . The question i asked is asked completely by my second response. Sorry about that.
 
  • #7
mg1977 said:
No, there aren't many examples in the book on this . The question i asked is asked completely by my second response. Sorry about that.

Look at the link in my post #2. It has the equations you need for calculations of linear coefficients of expansion.
 

1. How does thermal expansion affect steel rule and vycor glass brick?

Thermal expansion is the tendency of a material to expand or contract in response to changes in temperature. This can cause steel rule and vycor glass brick to expand or contract, potentially leading to dimensional changes and stress in the material.

2. What factors affect the thermal expansion of steel rule and vycor glass brick?

The thermal expansion of steel rule and vycor glass brick is influenced by several factors, including the type and composition of the material, temperature range, and the presence of impurities or defects.

3. Can thermal expansion cause damage to steel rule and vycor glass brick?

In extreme cases, thermal expansion can cause damage to steel rule and vycor glass brick, especially if the material is not able to withstand the stress caused by the expansion. This can result in cracks, warping, or even failure of the material.

4. Is thermal expansion a reversible process in steel rule and vycor glass brick?

Yes, thermal expansion is a reversible process in steel rule and vycor glass brick. As the temperature changes, the material will expand or contract accordingly, and will return to its original size and shape when the temperature returns to its initial value.

5. How can thermal expansion be managed in steel rule and vycor glass brick?

To manage thermal expansion in steel rule and vycor glass brick, engineers and scientists use techniques such as selecting materials with lower coefficients of thermal expansion, designing structures to allow for expansion and contraction, and using joints or gaps to accommodate the changes in size of the material.

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