## PHYS208 Fundamentals of Physics II

### Hint for Ch. 23, 3E

See *HRW* Fig. 23-5.

### Hint for Ch. 23, 17P

Use symmetry. Notice that the resultant of the forces from 12 and 6 has the same magnitude as the resultant of the forces from 1 and 7.

### Hint for Ch. 23, 22P

You may reduce each of the 4 field contributions if you wish and then sum;
HOWEVER, I would highly recommend that you make a sketch, consider the symmetry of the situation, and work out the resultant direction without numbers.
Definitely save substitution of the numerical values until the very last step!

### Hint for Ch. 23, 52P

Use kinematics to find the acceleration of the electron.
The electric field follows, knowing the
mass and charge on an electron and applying Newton's second law.

### Hint for Ch. 23, 57P

Dig out your PHYS207 notes. Once you determine the acceleration of the electron, this exercise reduces to a refresher of kinematics.

"http://www.physics.udel.edu/~watson/phys208/exercises/hints/0213.html"

Last updated Feb. 17, 1998.

Copyright George Watson, Univ. of Delaware, 1997.