Question

An iron bolt of mass 80.0 g hangs from a string 38.8 cm long. The top end of the string is fixed. Without touching it, a magnet attracts the bolt so that it remains stationary, displaced horizontally 28.0 cm to the right from the previously vertical line of the string.
(a) Find the tension in the string.
(b) Find the magnetic force on the bolt.

Answer 1

The string makes an angle of sin^-1 28/38.8 = 46.2 degrees with the vertical.

Do a force balance in vertical and horizontal directions.

T cos 46.2 = Weight = m g
Solve for T, the tension. Then use this equation.

T sin 46.2 = magnetic force

Answer 2

Thanks so much for your help drwls!!