Thursday, 10 March 2016

homework and exercises - Finding the terminal velocity of a magnet dropped in a solenoid




We have to find proportionality of the terminal velocity with the factors of the system: enter image description here


Plot: a small dipole(mass m) with dipole moment μ is dropped in a long solenoid (radius r, Resistance RΩ) along it's axis. The gravity is acting downwards.



I found it to be vmRμ2r


Here is how:



The force in downward direction Fdown must be mg and in upward direction Fup must be magnetic force. FupμIinducedr


Iinducedelectric flux changeRμπr2vR




Flux change depends directly on the velocity, so added v in the numerator. But the expression is not correct. The proportionality on the r radius is not correct. I think there is a problem in the induced current factor.




No comments:

Post a Comment

Understanding Stagnation point in pitot fluid

What is stagnation point in fluid mechanics. At the open end of the pitot tube the velocity of the fluid becomes zero.But that should result...