1. The problem statement, all variables and given/known data determine the terminal voltage in each battery. Emf_{1}=18V r_{1}=1 ohm EMF_{2}=12V r_{2}=2 ohm R=6.6 ohms also the batterys currents are opposing each other. 2. Relevant equations Vab=emf-Ir 3. The attempt at a solution i used kirchnoffs rule to find the current I , 18-I6.6-12-I2-I=0 and got I= .625 then i thought i would just use Vab=emf-Ir to find the terminal voltage of each battery however im not getting the correct answer... could someone please explain this to me i have a test tomorrow morning and i really need to figure this out! the answers i got were 17.375 for the 18V batt and 10.75 for the 12V batt
Watch out for the current direction and the thus the polarity of the voltage drop it creates on the internal resistors. If current is being forced into a battery's positive terminal it's possible for it to have a higher terminal voltage than its internal EMF.
so on the larger voltage batt would i use equation Vab=Emf-Ir = 18-(.625*1) and on the batt with voltage being forced across it use Vab=Emf+... idk
Yes. It can be helpful to sketch in your current and the polarities of the voltage drops across the resistors. You did fine writing the KVL loop equation.