Magnetic levitation A metal rod of length w = 15 cm and mass m = 70 grams has metalloops at both ends, which go around two metal poles (see thefigure).
The rod is in good electrical contact with the poles but can slidefreely up and down. The metal poles are connected by wires to abattery, and a current I = 9 amperes flows through the rod. Amagnet supplies a large uniform magnetic field B in the region ofthe rod, large enough that you can neglect the magnetic fields dueto the 9 ampere current. The large magnetic field is oriented tohave the maximum effect.
The rod floats at rest h = 9 cm above the table. What is themagnetic field in the region of the rod? Assume +x is to the right,+y is up, and +z is out of the page.
< 1, 2, 3> T
Which of the following statements are true? 4 The magnetic force on the bar is in the +y direction(upward). If the conventional current in the bar were less than 9 A, the barwould fall. If the conventional current in the bar flowed in the oppositedirection (to the left), the bar would still float at rest 9 cmabove the table.
