Coulomb\'s law for the magnitude of the force F between two particles with charg
ID: 1471718 • Letter: C
Question
Coulomb's law for the magnitude of the force F between two particles with charges Q and Q separated by a distance dis
|F|=K|QQ|d2,
where K=140, and 0=8.854×1012C2/(Nm2)is the permittivity of free space.
Consider two point charges located on the x axis: one charge, q1 = -12.5 nC , is located at x1 = -1.660 m ; the second charge, q2 = 32.0 nC , is at the origin (x=0.0000).
Part A
What is the net force exerted by these two charges on a third charge q3 = 48.5 nC placed between q1 and q2 at x3 = -1.050 m ?
Your answer may be positive or negative, depending on the direction of the force.
Explanation / Answer
A)
Force on q3 due to q1:
F1 = k*q1*q3/r1^2
where r1 = (1.66 - 1.05) = 0.61 m
So, F1 = 9*10^9*(12.5*10^-9)*(48.5*10^-9)/0.61^2
So, F1 = 1.47*10^-5 N
Force on q3 due to q2
F2 = k*q2*q3/r2^2
So,
F2 = 9*10^9*(32*10^-9)*48.5*10^-9/1.05^2
So, F2 = 1.27*10^-5 N
So, net force :
Fnet = F1 + F2
So, Fnet = 1.47*10^-5 + 1.27*10^-5 = -2.74*10^-5 N