Your 20-kg brother Mickey is on a see-saw. If you have a mass of 50-kg and are 2 meters away from the center of the see-
saw, how far out would Mickey have to sit if he wants to apply
the same force onto you that you apply onto him? meters

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.