Formula for pull force of a ring magnet on a metal rod

[kvkskumar]

Hi,
Can somebody give me the formula for pull force of ring magnet(permanent. not solenoid or electric) on a metal rod.

Also is the formula for pull force by a solenoid given below correct. If not let me know the correct one for the below.

Force = ((N x I)^2 x μ x A) / (2 x g^2)

N = the number of turns in the solenoid
I = the current, in amperes (A), running through the solenoid
A = the cross-sectional area, in meters-squared, of the solenoidal magnet
g = the distance, in meters, between the magnet and the piece of metal
μ = 4 x pi x 10^-7
^ = symbol that means "to the power of"

 

[Vailanor]

Yes, the formula for the pull force of a solenoid is correct. The formula for the pull force of a ring magnet on a metal rod is: Force = (μ x m x I) / (2 x g) where μ = 4πx10^-7 m = magnetic moment of the ring magnet I = current in the winding of the ring magnet g = distance between the ring magnet and the metal rod