Electric Potential and Charges Problem

[buyerat]

Homework Statement

Point P is at the origin. Charge A is at (-3,0) and Charge B is at (4,0). What is the electric potential at point P. Let's assume they are both positive charges for now, but I am interested to know if and how it changes if either/both of the charges are negative.

Homework Equations

I assume I will need to use V=kq/r but I could be mistaken.

The Attempt at a Solution

Once I get both the potentials using V=kq/r can I simply add them together to get the potential at P? If one charge was negative do I subtract the potential from that one from the positive charge to get the potential at P?


Thank you

 

[zachzach]

Homework Statement

Point P is at the origin. Charge A is at (-3,0) and Charge B is at (4,0). What is the electric potential at point P. Let's assume they are both positive charges for now, but I am interested to know if and how it changes if either/both of the charges are negative.

Homework Equations

I assume I will need to use V=kq/r but I could be mistaken.

The Attempt at a Solution

Once I get both the potentials using V=kq/r can I simply add them together to get the potential at P? If one charge was negative do I subtract the potential from that one from the positive charge to get the potential at P?


Thank you

Yes, you can use Kq/r to calculate the potential due to each charge at P. The great thing about using potentials is that it is a scalar and you can just add them. If you were using the E-field you would have to add the vectors which is more difficult. If charge is negative then it makes the potential negative since v = kq/r, so if q is negative then v will be negative as well.

 

[buyerat]

Thank you very much for the quick help. I thought I was on the right track but wanted to get some expert help :D.

Thanks again

 

[tiny-tim]

Hi buyerat!

Once I get both the potentials using V=kq/r can I simply add them together to get the potential at P? If one charge was negative do I subtract the potential from that one from the positive charge to get the potential at P?

Yup! … potentials add just like numbers.