It is in Section 8.9 of the textbook
I was going through this very old discussion thread (ttp://www.physicsforums.com/showthread.php?t=307728) and i came across this marvellous formula that you had quoted in this post of yours:
"That formula is for a pole far away from another pole.
The force depends on just where the magnet is put.
If the bar magnet is placed just at the end of the solenoid, then the force is given by F=BB'A/(2pi), where B and B' are the strengths in gauss, and A is the cross-sectional area of the bar magnet
This formula can work wonders for me, would you be so kind to send me a link to any source for it?