P=IV
therefore
V=P/I
P= W/T
W=F*D
and F=kgms^-2 (F=ma=Kg*ms^-2)
therefore
V=F*D/T and this divided by I
F*D/T gives Kgms^-2 * m * s^-1 ( the time at the denominator) = Kgm^2s^-3
and then current is A and since its a denominator in the equation then its A^-1
therefore, V= Kgm^2s^-3A^-1