# Calculating Q (dot)

1. Dec 9, 2008

### skaboy607

Hi

Wondering if someone could help me satisfy my curiosity. Hopefully a very simple for someone who knows. I have been given values for Voltage and Current. To calculate Q (dot), I know Q(dot)=V * A. The units for this are Watts / J/s / Nm/s.. How can Voltage multiplied by a current provide these units?

Thanks

William

2. Dec 9, 2008

### tiny-tim

Welcome to PF!

Hi William! Welcome to PF!

From electric units in the PF Library

Power = voltage.current = energy/time (dim. $ML^2/T^3$):

$$\text{W}\ \equiv\ \text{watt}\ \equiv\ \frac{\text{J}}{\text{s}}\ \equiv\ \frac{\text{joule}}{\text{second}}\ \equiv\ \frac{\text{N.m}}{\text{s}}\ \equiv\ \frac{\text{newton.metre}}{\text{second}}\ \equiv\ \text{V.A}\ \equiv\ \text{volt.amp}\ \equiv\ \Omega\text{.A}^2\ \equiv\ \text{ohm.amp}^2$$

3. Dec 9, 2008

### skaboy607

Thank you very much. Good to of joined.

Thats that sorted then, thanks for clearing up.

William