# EPE and mass of ion

1. Jun 15, 2015

### Fluxxx

1. The problem statement, all variables and given/known data
An ion, starting from rest, accelerates from point A to point B due to a potential difference between the two points. Does the electric potential energy of the ion at point B depend on it's mass?

2. Relevant equations
$$\Delta EPE = q \Delta V$$
$$[J]=[C\cdot \frac{J}{C}]$$
$$[J]=[N\cdot m]=[\frac{kg\cdot m^2}{s^2}]$$

3. The attempt at a solution
As can be seen in the third equation, the unit of EPE, [J] is given by it's mass [kg]. So the answer should be yes? Why is it not?

2. Jun 15, 2015

### Matternot

Look at equation 1

" $$\Delta EPE = q \Delta V$$ "

Does the EPE here depend on mass?

3. Jun 15, 2015

### Fluxxx

Yes, since EPE depends on V and V depends on mass.

$$[V]=[\frac{J}{C}]=[\frac{N \cdot m}{C}] = [\frac{kg \cdot m^2}{C\cdot s^2}]$$

4. Jun 16, 2015

### Matternot

Who says it depends on mass? just because it includes kg in the units doesn't mean it depends on mass. If V=5 JC-1 everywhere, it doesn't matter how much you weigh... it's still 5.