Hola!
Percentage Error is a measurement of the discrepancy between an observed and a true, or accepted value.
[ refer the attachment. ]
According to Question,
% error =

× 100
= 2.631 % = 2.7 % (approximately.)
hope it helps!
Larger mass creates a stronger pull
Yes I'm pretty sure you can
Place the magnet at one end of the piece of metal. The magnet must make as much contact with the metal as possible. Place light pressure on the magnet and rub the metal in one direction only. Magnetization will take some time to accomplish so continue rubbing until the iron or steel attracts other pieces of metal.