Solving Battery & Current Homework Problem: V, i, R, Power, Energy

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The discussion revolves around solving a physics homework problem involving current, voltage, resistance, and power in a circuit with multiple batteries and resistors. The main queries include calculating the current i1, and the power and energy dynamics of three different batteries (18 V, 10 V, and 5 V). Participants emphasize the importance of correctly combining resistances in series and parallel to simplify the circuit before applying Ohm's Law (V = iR). The original poster expresses confusion about which resistances to use and how to calculate the current, but ultimately resolves their issue independently. The thread highlights the typical approach to circuit analysis in a Physics II context.
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Homework Statement


Please help!:confused:

My problem is: (with figure attached, the figure explains the majority of the ptorblem)
(a) What is the size and direction of current i1 in Fig. 27-40, where each resistance is 2.2 and V1 = 18 V?

(b) What is the power of the 18 V battery, and is energy being supplied or absorbed by the battery?

(c) What is the power of the 10 V battery, and is energy being supplied or absorbed by the battery?

(d) What is the power of the 5.0 V battery, and is energy being supplied or absorbed by the battery?

Homework Equations


V=iR

The Attempt at a Solution


For part (a) I'm having trouble firguring out which resistances to use. Do I use all of the resistances and add them up according to whether they are parallel or perpendicular? Then, when I get the resistance that I need, do I just use the 10 V battery as my voltage to calculate the current? I tried adding all of the resistances and I got 8.64 ohms. Is this correct?

For part (b) I need to know again what resistance to use to calculate the current, which I would need to calculate power. If I can get some help on (b), I can probably do (c) and (d) by myself.
 

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In general, the best place to start such problems is to compute your lump resistances together whenever possible using the rules for addition in series and parallel. Then redraw the diagram with these. In this case you should end up with three R's and three voltages. Then one can start to develop some meaningful equations which will answer all of the above questions. Out of curiosity, what course is this for?
 
This is for Physics II. I understand how to lump the resistances together, i.e. parrallel and perpendicular. However, I am not sure how to calculate the amps. For example, for the left side, do I take the 5 volts and divide it by 0.88 ohms and then add that to 10 volts divided by 3.3 ohms (the resistance at the bottom left and bottom of the picture?
 
Nevermind. I figured out the problem.
 

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