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1. A steel bar has a rectangle cross section of 50mm by 40mm and is 2.0m long. Calculate the work done in extending it by 6.0mm. someone please help explain how to do this question, even just the formula will be helpful
2. (Original post by amy_elizabeth64)
A steel bar has a rectangle cross section of 50mm by 40mm and is 2.0m long. Calculate the work done in extending it by 6.0mm. someone please help explain how to do this question, even just the formula will be helpful
Moved to the Physics forum for you . They may be better placed to help you
3. (Original post by amy_elizabeth64)
A steel bar has a rectangle cross section of 50mm by 40mm and is 2.0m long. Calculate the work done in extending it by 6.0mm. someone please help explain how to do this question, even just the formula will be helpful
Work done is (average) force x distance.

In this case you have the distance the force has moved through. It's the extension.

When extending a rod or spring there is a formula for work done in terms of this extension (x) and the force (F) required to extend the rod.

Do you know this formula?

You now need to find the force.

There is a formula (relating to Young's Modulus) which will give you this force in terms of stress and strain. The information in the question gives you what you need to find strain and the force is found from the stress and cross sectional area.

Can you do it now?

You need a value for the Young Modulus for steel to do this. I presume you are given it or have a data sheet.

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