Announcements
 

18.6 Concepts

The electron and proton will feel the same amount of force, but since the electron has much less mass than the proton, it will accelerate more and reach the origin first.

18.14 Problems

Q₁ = - 3.00 mC

Q₂ = - 4.00 mC

Q₃ = +5.00 mC

r₁₂ = r₁₃ = 0.100 m

F₂₁ =  10.8 N south (270 degrees)

F₃₁ =  13.5 N east (0 degrees)

Magnitude of F₂ = 17.1 N

Direction of F₂ = 37.9 degrees south of east (322.1 degrees)

Concept 18.10

If the second charge, placed at the same location, feels a force that is different in both magnitude and direction, then the second charge must have a charge that is different in polarity and magnitude from the first.

Problem 18.27

To balance, the electric force must be the same size as the weight of the ball:

F_elec = F_grav

qE = mg

(-18 x 10^-6 C) E = (0.012 kg) (9.8 m/s²)

E = 6.5 x 10³ N/C

Assignments

Who is he?
Hint:  F = k (q₁q₂)/r²