222 Week 6: Moving Charges and Magnetic Force
Homework for Week 6
Problem 1.
Physics Concepts
Make this week’s physics concepts summary as you work all of the problems in this week’s
assignment. Be sure to cross-reference each concept in the summary to the problem(s) they were
key to. Do the work carefully enough that you can (after it has been handed in and graded) punch
it and add it to a three ring binder for review and study come finals!
Problem 2.
A particle with massmand chargeqa has a velocity~vperpendicular to a uniform magnetic field
B~(with magnitudeB=|B~|). Find: a) the radiusRof its orbit; b) the period of the orbit; c) the
momentum of the particle; d) the kinetic energy of the particle. All answers but the first should be
in terms ofq,m,BandR– novshould appear in b-d.
Problem 3.
A rigid circular loop of wire with massm,Nturns and radiusRcarries a currentIin each turn and
is sitting on a rough table. There is a horizontal magnetic fieldBthat is parallel to the surface of
the table in some direction (call itx). What is the minimum value ofBsufficient to lift on edge of
the loop off of the table? On your figure, clearly indicate which edge lifts relative to the directions
you select forIandB.