Question

Two iron rails, each 50 feet long, are laid end to end with no space between them. During the summer, the heat causes each rail to increase in length by 0.04 percent. Although this is a small increase, the lack of space at the joint makes the joint buckle upward. What distance upward will the joint be forced to rise? (Assume that each rail remains straight, and that the other ends of the rails are anchored. Round your answer to the nearest hundreth.

Answer 1

Good question.
First calculate the increase in length for each rail.

Answer 2

Which is 0.04% of 50
= 0.04/100 * 50
= 0.04/2 = 0.02 feet.
So total increase in length(for both the rails together) is 0.04 feet.

Answer 3

I think that should be the answers but lets wait for others' opinion.

Answer 4

Which is the answer? 0.04 ft or.....I'm a bit confused.

Answer 5

The question is by how much feet the move upwards(at the centre). As I said, I think its 0.01 feet but lets for someone else to see the question.
Can you bump it?

Answer 6

Okay! Why would it be 0.01 though?

Answer 7

Wouldn't it be 0.04

Answer 8

Lets say both the rails increase by 0.01 feet on each of their ends. So at the center they increase by 0.01 feet(each). Got that?

Answer 9

But they both increase by 0.02.....we know that.

Answer 10

Oh...on each of their ends. I understand now.

Answer 11

Yes. If each rail increases by 0.01 feet on BOTH sides then the total increase would be 0.02 right?

Answer 12

Right....so they would push it upward 0.02 no?

Answer 13

No, that's the tricky part. They are placed together with no distance between them. Just try to picturise it and you'll understand why its 0.01 not 0.02.