Question

the resistance of a wire varies directly with its length and inversely with the square of its diameter. if 100 feet of wire with diameter .01 inch as a resistance of 10 ohms, what is the resistance of 60 feet of the same type of wire is it diameter is .02 inch?

I need help setting it up.

Answer 1

\[r = k\frac{ l}{d^2}\]

Answer 2

with is r? and which is k?

Answer 3

r = resistance
d = diameter
l = length
k = constant of variation

Answer 4

All you have to do is plug in all the given values to find k

Answer 5

r= .15 ?

Answer 6

oh no the answer is r=1.5

Answer 7

Is that the book answer?

Answer 8

or your answer?

Answer 9

I'm asking because I got something different for r

Answer 10

both the books answer and my answer, the first answer I entered it wrong into my calculator so thats why I got .15 and then I entered it again then realized I added wrong.

Answer 11

Okay, I guess.

Answer 12

Strangely, I ended up getting r = 3.0 ohms

Answer 13

That is strange, how did you come up with that answer?