Two point charges are a small distance apart. a. Sketch the electric field lines for the two if one has a charge four times that of the other and both charges are positive.
b. Repeat for the case in which both charges are negative.

Explanation:

We know that, like charges repel and unlike charges attract each other.

IF one of the charge is four times that of the other and both charges are positive, the field lines is shown in figure (1).

Two negative charges attract each other, the field lines is shown in figure (2).

The net force between charges is given by :

Whre

k is the electrostatic constant

r is the distance between charges

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day