Physics Homework Help

Question

Coulomb's law for the magnitude of the force F between two particles with chargesQ and Q′ separated by a distance d is

|F|=K|QQ′|d2,

where K=1/4πϵ0, and ϵ0=8.854×10−12C^2/(N⋅m2) is the permittivity of free space.

Consider two point charges located on the x axis: one charge, q1 = -16.0 nC, is located at x1 = -1.725 m ; the second charge, q2 = 39.5 nC , is at the origin (x=0.0000).

What is the net force exerted by these two charges on a third charge q3 = 51.5 nC placed between q1 and q2 at x3 = -1.210 m ?

Your answer may be positive or negative, depending on the direction of the force.

Answer 1

Step 1:

Two point charges are located on - axis.

One point charge is .

First point charge is located at the .

Second point charge is .

First point charge is located at the origin m.

Third point charge of is placed in between at

Since the point chareges and are unlike, they attracts each other.

Coulomb's law: , where .

Find the force on due to .

Disatance between  and  is

Substitute , and in 

Step 2:

Find the force on  due to .

Disatance between  and  is .

Substitute , and  in .

N.

This force is also in the direction of left .

Net force on point charge is .

N.

Solution:

 N.