# Analyzing the Speed of a Permanent Magnet in a Coil

• onoi
In summary: This is due to the electrical energy generated by the magnet passing through the coil. The generated power can be calculated using Faraday's law, and in this scenario, the power generated is 5.12 watts. This energy is then subtracted from the initial kinetic energy of the magnet (9 joules) to determine the remaining kinetic energy and thus the speed after exiting the coil. So, in summary, the permanent magnet will slow down upon exiting the coil due to the electrical energy generated by passing through the wire coil.
onoi
If a permanent magnet rod enters a coil of wires at a certain speed will the permanent magnet slow down? I'm trying to build a generator of some sort. So i need to know is my logic sound. I'll give you scenario.

Scenario:

The permanent magnet slides into the coil at a speed of 3meters/second. What will the speed of the magnet be after exiting the coil?

Permanent magnet parameters
Mass : 2kg
Strength : 2000Gauss or 0.2Tesla
Area : 0.008m2

Wire Coil Parameters
Turns : 20000
Resistance : 50 Ohm
Length of Coil : 3meters

Thus the energy contain in the magnet moving at 3ms-1 is = 9joules

E=1/2 mv^2
E=(1/2)(2)(3^2)
E=9Joules

So using faradays law, the power generated by the magnet passing thru the coil of wire :

V= (-N)(BA/t)
V = voltage
N = Turns
B = Flux (in tesla)
t = Round per second
A = Surface Area of permanent magnet

Note : I will reduce the flux strength to 0.1tesla because the coil will be approximately 2mm from the magnet

V = (-20000)(0.1*0.008*/1)
V = 16Volts

Thus the current generated is

I=V/R

I = 16V / 50ohm
I = 0.32amps

Thus power generated is

Power = VI
Power = 16V * 0.32amps
Power = 5.12Watts or joule per second

Thus the speed of the permanent magnet exiting the coil is

9joules – 5.12 joules = Kinetic Energy Remaining

3.88 = (1/2)(2)(v ^2)
v = √(3.88*2/2)
v = 1.96ms-1

Is this logic and calculation correct??

Your logic and calculations appear to be correct. The permanent magnet should exit the coil at a speed of 1.96m/s, which is slower than when it entered the coil.

## 1. How does the speed of a permanent magnet in a coil affect its performance?

The speed of a permanent magnet in a coil is directly related to its performance. The faster the magnet moves, the stronger the electromagnetic force generated by the coil will be. This force is what allows the magnet to interact with other objects and perform tasks such as generating electricity or moving objects.

## 2. What factors can affect the speed of a permanent magnet in a coil?

There are several factors that can affect the speed of a permanent magnet in a coil. These include the strength of the magnetic field, the size and shape of the magnet, the composition of the coil, and the resistance of the circuit. Additionally, external factors such as friction and air resistance can also impact the speed of the magnet.

## 3. How is the speed of a permanent magnet in a coil measured?

The speed of a permanent magnet in a coil can be measured using a variety of methods, depending on the specific application. In general, the speed can be determined by measuring the time it takes for the magnet to travel a certain distance or by using sensors to detect the movement of the magnet. Specialized equipment such as tachometers or speedometers may also be used.

## 4. What are some real-world applications of analyzing the speed of a permanent magnet in a coil?

Analyzing the speed of a permanent magnet in a coil has numerous real-world applications. One of the most common is in electric motors, where the speed of the magnet determines the speed of the motor and thus the speed of the machine it is powering. Other applications include generators, magnetic levitation systems, and magnetic sensors used in various industries.

## 5. How can the speed of a permanent magnet in a coil be optimized?

The speed of a permanent magnet in a coil can be optimized by adjusting the various factors that affect its performance. This could involve increasing the strength of the magnetic field, using a more efficient coil design, or reducing external factors that may slow down the magnet. Additionally, using specialized materials or techniques can also improve the speed and overall performance of the magnet in a coil.

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