Register to reply

Parallel Wires

by Touchme
Tags: parallel, wires
Share this thread:
Mar5-07, 11:14 PM
P: 41
1. The problem statement, all variables and given/known data
Two long parallel wires, each with a mass per unit length of 43 g/m, are supported in a horizontal plane by 6.0 cm long strings, as shown in Figure P19.64. Each wire carries the same current I, causing the wires to repel each other so that the angle between the supporting strings is 16°.
Determine the magnitude of each current.

2. Relevant equations
sin (theta) = opposite/hyp

I^2 = [(2pi)(d)(mg/L)] / [(4pi)e-07]

3. The attempt at a solution

First I found d (the distance between the wires). Which is 2[sin(8)](0.06m) = 0.0167m.
Then I substitute the given into this equation: I^2 = [(2pi)(d)(mg/L)] / [(4pi)e-07]. I = sq.root of [(2pi)(0.0167)(0.043)(9.8)] / [(4pi)e-07]. the answer I got is 132.64 A. What did I do wrong?

I tried using free body diagram.
T = mg/sin8
Tcos8 = [(I^2)(L)((4pi)e-7)] / [(2pi)d]
(mgcos8)/(sin8) = [(I^2)(L)((4pi)e-7)] / [(2pi)d]
(mg/L)(7.115) = [(I^2)((4pi)e-7)] / [(2pi)0.0167]
I = 159.8 A

Still incorrect.
Attached Thumbnails
Phys.Org News Partner Science news on
Bees able to spot which flowers offer best rewards before landing
Classic Lewis Carroll character inspires new ecological model
When cooperation counts: Researchers find sperm benefit from grouping together in mice
Mar5-07, 11:36 PM
P: 41
Ah shoot, I've made the most stupid mistake ever. I solved it.

Register to reply

Related Discussions
Magnetic forces between parallel wires Introductory Physics Homework 7
Force between two parallel wires Introductory Physics Homework 1
Two Parallel Wires( in 2 hrs!) Introductory Physics Homework 14
Two wires in parallel and capacitence Advanced Physics Homework 1
Parallel wires Introductory Physics Homework 9