Question

Cari wants to show her class how magnets can lift objects off her desk. Cari has a few magnets that look like the one shown below. There are two iron objects on her desk. One object is larger than the other.

circular, flat magnet

She slowly brings one of the magnets close to the smaller object. The smaller object then lifts off the desk and attaches to the magnet.

The larger object on Cari's desk is attracted to the magnet, but is not able to lift off of Cari's desk. What should Cari do to show the class she can lift the larger object off the desk?
A.
rub one of the magnets with a balloon and move the magnet farther away from the larger object
B.
stack one magnet on top of another and bring them close to the larger object
C.
rub one of the magnets with cloth or hair and move the magnet closer to the larger object
D.
stack one magnet on top of another and move the magnets farther from the larger object

Answer 1

B

Stacking the magnets increases their combined magnetic field (if you align the poles) and bringing them closer increases the magnetic force on the object. Rubbing with a balloon or cloth produces static electricity, not stronger magnetism, and moving the magnet farther away reduces the force.