How Does a Rail Gun Work Without an External Magnetic Field?

In summary, the conversation discusses the concept of Faraday's Law and Lenz's Law in relation to a rod placed between two rails. The participants question why the rod would experience a force if there is no external magnetic field, to which the explanation is that the change in magnetic flux is not instantaneous and there is still some flux present to induce a current and force on the rod. The conversation also mentions that the example in the video involves an external magnetic field and explains the transient effect of the induced current.
  • #1
jsmith613
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http://www.brightstorm.com/science/physics/magnetism/faradays-law-lenzs-law/#

Start at about 7:10 and watch until about 8:20.
I can see that an emf and hence a current will be induced in the rod between the two rails BUT if there is no external magnetic field (the magnetic field generated by the rod due to the current flowing in it is irrelvant) then why would the rod experience a force...

the only explanation I can think is that the change in magnetic flux is NOT instantaneous...therefore as it is reducing (might take 0.1 ms to completely dissapear) there is still some flux to apply a force to the rod...is this correct?
 
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  • #2
Um - the example in the video has an external field.
When you switch the field off, the flux through the loop goes to zero - creating an EMF, which gives the rod (and everything else) a kick.

The transient effect for these things is usually quite complicated and a bit beyond the level of the video. For instance, as you have noted, the induced current also has a magnetic field.
 

What is a rail gun?

A rail gun is a weapon that uses electromagnetic force to launch a projectile at extremely high velocities. It consists of two parallel rails, a power supply, and a conductive projectile. When a large amount of current is sent through the rails, it creates a magnetic field that accelerates the projectile along the rails and out of the gun.

How does a rail gun work?

A rail gun works by using electromagnetic force to accelerate a conductive projectile to high speeds. When a large current is sent through the rails, it creates a magnetic field that pushes against the projectile, propelling it forward. The rails also act as conductors, allowing the current to flow through them and create the magnetic field.

What is the advantage of using a rail gun?

The main advantage of using a rail gun is its ability to launch projectiles at extremely high velocities. This can be beneficial in military applications, as it allows for greater range and accuracy compared to traditional firearms. Rail guns also have fewer mechanical parts, making them more reliable and easier to maintain.

What are the potential uses of a rail gun?

Rail guns have a variety of potential uses in both military and civilian applications. In the military, they could be used as long-range artillery or anti-aircraft weapons. They could also be used in space travel, as the lack of atmosphere allows for even higher velocities. In civilian applications, rail guns could be used for launching satellites into orbit or as a more efficient means of transportation.

What are the limitations of a rail gun?

One of the main limitations of a rail gun is the amount of energy required to launch a projectile at high velocities. This can be a challenge to overcome, as it may require large and expensive power sources. Additionally, the rails of a rail gun can experience significant wear and tear due to the high currents and forces involved, which can limit its lifespan and require frequent maintenance.

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