# Acceleration and induction

1. Jul 27, 2010

### Gavroy

Hey, I am not from an english-speaking country, so excuse my art of writing english please:uhh:

My question is about the eddy current brake that is used by for example the roller coaster.
Does anyone know whether this brake procedure happens with constant acceleration?

For instance, when a free-fall tower breaks by using magnetic induction. Is there a constant acceleration or not?

2. Jul 28, 2010

### Gavroy

nobody can help me?

3. Jul 28, 2010

### htg

Eddy current will be proportional to the time derivative if flux of magnetic induction. This time derivative of flux will be proportional to speed if a permanent magnet is used (or an electromagnet of constant field strength). The braking force will be proportional to Eddy current which will be higher at hiher speed. So deceleration will be stronger at higher speeds.

4. Jul 28, 2010

### Gavroy

Does this mean that the time derivative of the deceleration is constant(I think this is called jerk?)

5. Jul 28, 2010

### htg

I think so, approximately.