Explaining Redistributed Charges on Pennies

(a) What is the final charge on each penny?

When two pennies are given charges of -q and +2q respectively, and they are brought together and touched, the charges redistribute so that the pennies end up with equal amounts of charge spread out over their surfaces. In this case, the final charge on each penny can be calculated as follows:

Final charge on each penny:

Since the charges on the pennies are redistributed, the final charge on each penny will be 1/3 of the initial total charge.

(a) The final charge on each penny is 1/3 q.

(b) Calculate the final charge on each penny if q is 30 uC (30 x 10⁻⁶ C).

When the initial charge q is equal to 30 uC (30 x 10⁻⁶ C), the calculation for the final charge on each penny with the redistributed charges can be done as follows:

Calculating the final charge on each penny:

Given q = 30 x 10⁻⁶ C:

Initial charge on penny 1, q₁ = -q = -30 x 10⁻⁶ C

Initial charge on penny 2, q₂ = +2q = 60 x 10⁻⁶ C

Charge when the pennies touch = q = 30 x 10⁻⁶ C

Final charge on each penny after redistribution = q/2 = 15 x 10⁻⁶ C = 15 µC

(b) The final charge on each penny is 15 µC. q = 30 uC (30 x 10⁻⁶ C)

Therefore, when the two pennies with charges -q and +2q are brought together and touched, the redistributed charges cause each penny to end up with 15 µC of charge spread out over their surfaces, resulting in equal amounts of charge on each penny.