Charged Particles (Potential Energy)

[kilnvzol]

Homework Statement

Figure 24-21 shows four pairs of charged particles with identical separations. (a) Rank the pairs according to their electric potential energy (that is, the energy of the two-particle system), greatest (most positive) first. (b) For each pair, if the separation between the particles is increased,does the potential energy of the pair increase or decrease?

Homework Equations

U = W = (kq₁q₂)/r

The Attempt at a Solution

For part a, I got the ranking 3,2,4,1 by subtracting the second particle from the first one. ie. (1) -2-(+6) = -8
For part b, I got 1,4 increase whereas 2,3 decrease from the equation.
I haven't gotten the answers to these but I want to make sure I'm right.
Thank you!

 

[SammyS]

Homework Statement

Figure 24-21 shows four pairs of charged particles with identical separations. (a) Rank the pairs according to their electric potential energy (that is, the energy of the two-particle system), greatest (most positive) first. (b) For each pair, if the separation between the particles is increased,does the potential energy of the pair increase or decrease?

Homework Equations

U = W = (kq₁q₂)/r

The Attempt at a Solution

For part a, I got the ranking 3,2,4,1 by subtracting the second particle from the first one. ie. (1) -2-(+6) = -8
For part b, I got 1,4 increase whereas 2,3 decrease from the equation.
I haven't gotten the answers to these but I want to make sure I'm right.
Thank you!

Not correct.

Did you use the relevant equation ?

 

[kilnvzol]

Not correct.

Did you use the relevant equation ?

Would this be right?
a. 3=4>2=1
b. 3&4 decrease 1&2 increase

 

[SammyS]

Would this be right?
a. 3=4>2=1
b. 3&4 decrease 1&2 increase

That looks to be correct .

 

[kilnvzol]

That looks to be correct .

Thank you!