Wire Length

Algebra

Wire Length

Postby Guest » Sun Jan 10, 2021 8:00 pm

A coil of steel wire is 0.025 in. in diameter, and weighs 50 lbs. Steel weighs .29 lbs. / cu. ft. Find weight of the coil.

The wire is a cylinder.

Volume = Pi * r^2 * h.

3.1416 * 0.0125 * 0.0125 * h

Unsure how to proceed.
Guest
 

Re: Wire Length

Postby Baltuilhe » Mon Jan 11, 2021 10:09 am

Good morning!

[tex]m=50lbs\\
d=\frac{m}{V}\\
0,29=\frac{50}{V}\\
V=\frac{50}{0,29}\\
\pi\cdot R^2\cdot H=\frac{50}{0,29}\\
\pi\cdot\left(\frac{D}{2}\right)^2\cdot H=\frac{50}{0,29}\\
\pi\cdot\left(\frac{\frac{0,025}{12}}{2}\right)^2\cdot H=\frac{50}{0,29}\\
\pi\cdot\left(\frac{0,025}{24}\right)^2\cdot H=\frac{50}{0,29}\\
H=\frac{50\cdot 24^2}{0,29\cdot\pi\cdot 0,025^2}\\
H\approx 50\,578\,343,29ft[/tex]

Why such a long wire? :) Almost 9600 miles! :o

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Re: Wire Length

Postby Guest » Mon Jan 11, 2021 11:37 am

Good Morning!

Answer they gave: 29,270 ft. (nearly).

Thanks.
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Re: Wire Length

Postby HallsofIvy » Mon Jan 11, 2021 1:16 pm

The directions are "find the weight of the coil"!

It's 50 pounds!

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Re: Wire Length

Postby Guest » Mon Jan 11, 2021 1:57 pm

It should read: Find the length of the coil.

Weight was a typo. My apology.
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Re: Wire Length

Postby Guest » Mon Jan 11, 2021 2:20 pm

Also, another typo:

The .29 is lbs. / cu. in., not cu. ft.

My apology, again.
Guest
 


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