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"