Moving metal object in a magnetic field

• alikim
In summary, the change in trajectory of the bullet when attracted by the magnet does take energy, which comes from the Earth's motion due to the magnetic force acting on the magnet. This is similar to the concept of gravity, where the attractive force between two objects results in a change in motion for both objects.

alikim

Let's say I have a bullet flying by a magnet, the magnet will attract the bullet and change its trajectory so it will turn slightly. Does that trajectory change take energy? If it does, where does it come from? The kinetic energy of the bullet?

It's just like gravity, the attractive force acts on both objects. So if the magnet attracts the bullet with a force, the magnetic force is also pulling on the magnet. If the magnet is bolted to the earth, then the Earth's motion may change slightly. But since the Earth is much more massive than the bullet, the change will be barely noticed.

I don't know if you are assuming that the bullet is made of a magnetic material. It could be something like copper, but you can still have it affected by the magnet, due to the conductor's motion in a magnetic field. See Lenz's Law.

I understand that there are forces at play there. I'm asking about energy, see my OP.

scottdave said:
If the magnet is bolted to the earth, then the Earth's motion may change slightly. But since the Earth is much more massive than the bullet, the change will be barely noticed.
alikim said:
I understand that there are forces at play there. I'm asking about energy, see my OP.
He did answer your question. In the first case the energy comes from the Earth. There is a force applied through a small distance (the change in the Earth's position and/or rotation), which is equivalent to the work done to change the trajectory of the bullet.

It's the same as when you bolt a magnet to a table and place a ferrous ball nearby. The ball is pulled to the magnet because the Earth is exerting a force on the magnet which changes the Earth's motion imperceptibly.

1. How does a magnetic field affect a metal object?

A magnetic field can cause a metal object to experience a force and move in a particular direction. This is because the metal object contains electrons, which are negatively charged particles, and when placed in a magnetic field, they are affected by the magnetic force.

2. What is the relationship between the strength of the magnetic field and the movement of the metal object?

The strength of the magnetic field directly affects the movement of the metal object. A stronger magnetic field will result in a greater force acting on the metal object, causing it to move faster or in a different direction.

3. Can a metal object be moved in a magnetic field without direct contact?

Yes, a metal object can be moved in a magnetic field without direct contact. This is known as an induced current, where the changing magnetic field creates an electric current in the metal object, causing it to experience a force and move.

4. What is the significance of the orientation of the metal object in a magnetic field?

The orientation of the metal object in a magnetic field can affect the direction and magnitude of the force acting on it. This is because the force is dependent on the angle between the direction of the magnetic field and the direction of the current in the metal object.

5. How does the movement of a metal object in a magnetic field relate to the principles of electromagnetism?

The movement of a metal object in a magnetic field is a result of the interaction between electricity and magnetism, which are two fundamental forces of electromagnetism. The movement is governed by the principles of electromagnetism, such as the right-hand rule and Faraday's law of induction.