# Homework Help: Centrifugal equation

1. Jan 10, 2005

### Lorax

=mv^2
----------R
r

How do you calculate the r on the side?

Also is centrifugal force = to magnet force?

2. Jan 10, 2005

### dextercioby

Depends on the problem.Give us a specific problem & we'll tell how to compute the "r",if u really have no idea.
Nope,the magnetic force has a centripetal effect,not a centrifugal effect.

Daniel.

3. Jan 10, 2005

### Sirus

Lorax, don't forget that centrifugal force doesn't actually exist.

4. Jan 11, 2005

### dextercioby

WHAT??????????????????? :surprised :surprised :surprised :surprised :surprised :surprised :surprised :surprised :surprised It definitely exists.It's an inertial force (the name says:"centrifugal inertial force") and appears in every system which undergoes nonlinear movement.But only in the nonienrtial(accelerated) reference system.Did u ever go with a car/bus and took a turn...????????????????????????????????

Daniel.

5. Jan 11, 2005

### Lorax

In a particle accelerator, an alpha particle with a mass of 6.64 x10^-27 kg is moving with a speed of 2.50x10^7 m/s. It is moving perpendicularily through a magnetic field of intensity 0.150 T. Using appropriote equations and method find the radius of curvature of its path.

Hope that helps

6. Jan 11, 2005

### Sirus

When you take a turn in a bus, although it may seem like a force is pushing you against the wall of the bus, this is not infact occuring. The reason you feel pushed is because you instantaneous velocity at that point is tangental to your circular path; your body is trying to travel into the wall.

Draw a free-body diagram of an object in circular motion. Do you draw a force vector pointing out of the circle? I hope not...

I think you and I have the same understanding of this concept, but are debating the semantic aspect, which is ultimately useless. According to Wikipedia, which explains the concept well, centrifugal force is a fictitious force. Here is their explanation of that. I guess I must admit that centrifugal force does exist, but I do not think circular motion is best thought of using it, especially at the highschool level. It does not exist as a force the way other forces (such as the centripetal force) do in the inertial reference frame we are concerned with.

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Lorax:

In your question, the magnetic force is the centripetal force for the circular motion of the particle. Set $F_{m}$ equal to $F_{c}$, and try to develop an expression for radius as a function of things you can find, such as mass, velocity, magnetic field strength, etc.

7. Jan 11, 2005

### Curious3141

I prefer to consider only forces that are apparent to an inertial observer to be "real". It is convenient to think about centrifugal force as "real", but not completely correct in conventional mechanics.

For a more rigorous treatment of this, read the D'Alembert's formulation of Newton's laws to incorporate inertial forces.