2 parallel rods carrying the same current

In summary, the current in the rods is the same because the magnetic force between the rods is equal to the force of gravity.
  • #1
Dart82
57
0

Homework Statement


Two rigid rods are oriented parallel to each other and to the ground. The rods carry the same current in the same direction. The length of each rod is 0.70 m, while the mass of each is 0.071 kg. One rod is held in place above the ground, and the other floats beneath it at a distance of 8.2 10-3 m. Determine the current in the rods.

[URL=http://img53.imageshack.us/my.php?image=problem3ta5.gif][PLAIN]http://img53.imageshack.us/img53/5664/problem3ta5.th.gif[/URL][/PLAIN]



Homework Equations


F = ILBsin(theta)
B = (uI)/(2 pi r)



The Attempt at a Solution


i know that current will be the same for both rods and since the current is flowing in the same direction, the magnetic force will be attractive between the rods. i know the length of each wire and the mass. i don't know how to progress in this problem because it seems to me that i need to know the magnetic field to be able to solve either equation. is there a way to solve this problem without knowing the magnetic field or am i overlooking something here? I'm stumped.
 
Physics news on Phys.org
  • #2
Well you can have two equations with two unknowns, and it is possible to find both unknowns. Its kind of like solving for x and y with two algebraic equations. Only difference is that here, we have current and the magnetic field.
 
  • #3
i'm sorry but is there possibly another way to say what you just told me; i don't get it. Am i even using the correct formulas? if i try to use F = ILB sin(theta) and solve for I, i get stuck because i don't know how to find B. If i try to solve B=(uI)/(2 pi r) i run into the same situation.. i don't know I or B. I know this problem cannot be as hard as it seems to me...
 
  • #4
Okay so since the rods are not falling towards the Earth or each other, that must mean that the force between the rods is equal to that of gravity. So we have:
mg = ILB sin(theta)
B = (uI)/(2 pi r)

We know all the values for all variables there, except B and I. Now using a system of equations, can you solve for both B and I? You can use the method of substitution or elimination, whatever makes you happy.
 
Last edited:
  • #5
ok, i'll give it another shot. thank you.
 

FAQ: 2 parallel rods carrying the same current

1. How does the direction of current flow affect the behavior of two parallel rods carrying the same current?

The direction of current flow does not affect the behavior of two parallel rods carrying the same current. As long as the current is flowing in the same direction, the rods will experience the same forces and behave in a similar manner.

2. What happens when the current in one of the parallel rods is reversed?

If the current in one of the parallel rods is reversed, the rods will experience opposite forces and may move in opposite directions. This is because the current creates a magnetic field around the wire, and the direction of the current determines the direction of the magnetic field.

3. How does the distance between the parallel rods affect the strength of the magnetic field?

The closer the parallel rods are to each other, the stronger the magnetic field between them will be. This is because the magnetic field follows an inverse square law, meaning that the strength of the field decreases as the distance between the rods increases.

4. Can two parallel rods carrying the same current repel or attract each other?

Two parallel rods carrying the same current will experience a force of repulsion due to the interaction of their magnetic fields. This is because like currents create like magnetic fields, which repel each other.

5. What are some real-world applications of parallel rods carrying the same current?

Parallel rods carrying the same current are commonly used in devices such as electric motors and generators. They also play a crucial role in the operation of power grids, where multiple transmission lines carry the same current to distribute electricity to different areas.

Similar threads

Back
Top