Question

How much energy does it take to move a particle with a charge of +2 nC, from an initial position infinitely far from a second particle with a charge of +3 mC, to a final position 0.20 m from the second particle?

Answer 1

To solve this problem we will apply the concept related to the electric potential energy, defined from the laws of Coulomb for which it is necessary to,

$U = \frac{kq_1q_2}{r}$

Here,

k = Coulomb's constant

$q_{1,2}$= Charge of each object

r = Distance,

Our values are given as,

$q_1 = 2nC = 2*10^{-9}$

$q_2 =3mC =3*10^{-3} C$

$r = 0.2m$

Finally replacing we have that,

$U = \frac{kq_1q_2}{r}$

$U = \frac{(9*10^9)(2*10^{-9})(3*10^{-3})}{0.2}$

$U = 0.27J$

Therefore the energy necessary to move the particle is 0.27J