Hi I’m currently learning about P=V^2/R
I’ve been asked a question on how to use the dimensions of P and V to determine the dimensions of R.
I know that’s
\$P=ML^2T^{-3} \$
\$V=L^{0.5}M^{0.5}T^{-1} ~\$ where L only meant Unit of Length and M unit of mass and T=time.
Engineers in EU and other Internationals use U or U(t) for volts and mostly America uses V or V(t) yet on the right \$P=\dfrac{V^2}{R}\$
Why do they make this confusing? Is it inaccurate?
Best Answer
The chart breaks the electrical units down into the base units.
An ohm is defined in terms of amperes and volts. Amperes and volts are defined in terms of distances (in meters,) time (in seconds,) and mass (probably in grams.)
As I think the point of this exercise is to demonstrate the equivalence of electrical power and mechanical power, I'll just give you a hint:
Substitute the definitions for voltage, current, and power into the formula for electrical power (\$P=\frac{V^2}{R}\$). You should be able to see how they all relate when you do that.
I've been reminded that the ampere is a base unit. It can still, however, be described in terms of the simplest units (time, length, and mass.) The chart the OP was given uses only those three to show the interrelationship of all the units.