Magnetic Induction Through a Moving Wire

In summary, a conducting rod with a mass of 5 kg and a resistance of 8 Ohm is placed on a vertical u-shape conducting wire in a constant magnetic field of B = 0.9 tesla. The rod slides down the wire while maintaining good contact and reaches a maximum velocity. The equations used to solve for the maximum velocity and current in the loop are ε= v*L*B, I=(v*L*B)/R, F = I*L*B, and F = (v(L*B)^2)/R. The correct answer for the maximum velocity is 1.97m/s and the current in the loop is 1.56A.
  • #1
Broem
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0

Homework Statement


A very long u-shape conducting wire is placed vertically in a constant magnetic field. The magnetic field is perpendicular to the plane of the wire. The strength of the magnetic field is B = 0.9 tesla. A conducting rod is placed on the wire, as shown in the picture. The length of the rod is 7 m. The rod has a mass of 5 kg and a resistance of 8 Ohm. When the rod is released from rest, it start to slide down but maintain good contact with the u-shape wire. After some time, the rod reaches a maximum velocity and moves constantly thereafter. You can ignore the resistance of the u-shape wire and the friction between the rod and the wire.
B = 0.9T ; L = 7m ; R = 8Ω ; g= 9.8m/s
What is the maximum velocity of the moving rod?
What is the current in the loop when the moving rod reaches maximum velocity?

Homework Equations


ε= v*L*B
I=(v*L*B)/R
F = I*L*B

or
F = (v(L*B)^2)/R


The Attempt at a Solution



Ok I know that once this wire begins to move it creates an emf and a current. The magnetic force generated is going to counteract my force of gravity. My assumption is that when it reaches its maximum velocity the F will be 9.8 as well since it can no longer change.
So:
F = 9.8N?
I've tried plugging in from here and have not been able to get a correct answer, where am I going wrong?
9.8 = I(7)(0.9) thus I = 1.56A

1.56 = (v(7)(0.9))/8 thus v = 1.97m/s
 

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  • #2
As soon as I posted this I remembered that the F is ACTING on MASS. This makes my F = 49N
D'oh!
I'll leave this here I guess.
Plugging in it all worked out smoothly :)
 

1. What is magnetic induction through a moving wire?

Magnetic induction through a moving wire refers to the process of creating an electric current in a wire by moving it through a magnetic field. This phenomenon is based on Faraday's law of induction and is the underlying principle behind generators and motors.

2. How does magnetic induction through a moving wire work?

When a wire is moved through a magnetic field, the magnetic field exerts a force on the free electrons in the wire, causing them to move. This movement of electrons creates an electric current in the wire, which can be harnessed for various applications.

3. What factors affect the amount of induced current in a moving wire?

The amount of induced current in a moving wire depends on the strength of the magnetic field, the velocity of the wire, and the angle between the wire and the magnetic field. Additionally, the length and thickness of the wire can also affect the induced current.

4. How is magnetic induction through a moving wire used in everyday life?

Magnetic induction through a moving wire is used in many everyday devices, such as generators, motors, and transformers. It is also used in various forms of transportation, such as trains and electric cars, to convert the energy from the movement of the vehicle into electricity.

5. Are there any practical applications of magnetic induction through a moving wire?

Yes, there are many practical applications of magnetic induction through a moving wire. Some of the most common uses include generating electricity, powering electric motors, and transferring energy wirelessly through induction charging. It is also used in various industrial applications, such as welding and metal sorting.

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