This assignment is due before 9 AM, Friday, September 28^th, 2007.

Please type a nickname: (in case your answer gets used in class).

You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT HOMEWORK button at the bottom of this page.

WarmUp questions are worth 4 points.

1.

The force F experienced by a particle with charge q moving with velocity v in a magnetic field B is given by the equation F = q v x B. As a result, it is possible for a charged particle in a magnetic field to feel no force at all. Please describe the situations in which this occurs.

2.

In a color TV, an "electron gun" accelerates electrons through a potential of about 25,000 V. Calculate the speed of an electron from the gun, and estimate the acceleration such an electron would feel due to the Earth's magnetic field.

Hint: In Indianapolis, the Earth's magnetic field has a magnitude of about 5.5 X 10^-5 T.

3.

The force is zero.

The force is to the North

The force is to the South

The force is upward

The force is downward

The force is to the East

The force is to the West

You may change your mind as often as you wish. When you are satisfied with your responses click the SUBMIT button.