Solids- area and change in L

[combatwombat]

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If the area of a solid is doubled, how will this effect the fractional change in length?

 

[VCU07]

Are you talking in terms of elasticity? Remember that Pressure=F/A which is divided by delta L/L (delta P/delta L). Rearrange and solve.

 

[combatwombat]

can i get an answer? for some reason it just isn't clicking

seems like deltaL/L should have to go down by a factor of 2 as well to keep P constant

 

[FuSoYa]

doesnt it depend on what you're keeping constant? If L is constant, then deltaL is halved.

If L and deltaL both change, then their change will depend on each other. I think...

F/A is proportional to deltaL/L... if A is doubled, then the (deltaL/L) term is halved.

 

[combatwombat]

doesnt it depend on what you're keeping constant? If L is constant, then deltaL is halved.

If L and deltaL both change, then their change will depend on each other. I think...

F/A is proportional to deltaL/L... if A is doubled, then the (deltaL/L) term is halved.

Yeah, that's what I'm thinking. That's why it says fractional change in length - delta L could be changing, L could be changing, or both. But either way deltaL/L has to go down by half (I think)

 

[VCU07]

Yeah, that's what I'm thinking. That's why it says fractional change in length - delta L could be changing, L could be changing, or both. But either way deltaL/L has to go down by half (I think)

I agree, it would decrease by half. When you say fractional length, it makes me think of the whole equation (delta L/L), which rearranged gives:
delta L/L=F/A * E. So, it would have to dec. by half if area is dbl'd.

 

[Vihsadas]

Hey guys, remember to post these kinds of questions in the Study Q&A forum. Moving there now. Thanks and good luck! 🙂