Lab Report- Circuits Calculating Resistance and Current

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The discussion revolves around difficulties in calculating the resistance and current for a physics lab report involving a circuit with both series and parallel resistors. The user understands how to calculate equivalent resistance and battery voltage but struggles with the specifics of individual resistor calculations and voltage drops. They have attempted to break down the circuit into series and parallel components but remain confused about how to calculate the current and voltage for each resistor. Clarifications indicate that the user needs to focus on calculating the voltage and current across each resistor rather than their resistances, which they already have. Overall, the calculations and approach taken appear correct, but the user is primarily confused about the process rather than the physics itself.
Dhooy7
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I am struggling with doing calculations for a physics lab report. I understand how to calculate the equivalent resistance and the voltage of the battery. I am struggling with calculating the resistance of each resistor and the current of each resistor.

I am sorry but I am getting very frustrated because I looked in the book and tried to follow the examples, but the book examples were too simplified. They separated series and parallel resistors into two different examples. In my example, there is a circuit with the resistors in parallel and in series. Then, I talked to her again and he said to look in the book again and she won't help me. I am frustrated because she helped other students with it.

I need to calculate the resistance of each resistor and the current of each resistor. I can only use the resistances of each resistor and the voltage of the battery.

R1=10.44
R2=10.36
R3=10.12
R4=10.13

Vbatt=5.85 V

I attempted to the voltages and currents of each resistor but do not understand about breaking them down into parallel and series. Like for circuit 5, I broke them into series and parallel. Then how do I calculate the current of each resistor? Do I calculate the current, resistance and go back and forth? Also, voltage drops confuse me. I attached the work I have and what I attempted to do.

If someone could check it over to make sure I do it correctly that would be great and explain the process that would be amazing! It is due very soon and I don't know what to do.
 

Attachments

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Dhooy7 said:
Do I calculate the current, resistance and go back and forth?
In general, yes.
In circuit 5, finding the voltage at two resistors can be done without further calculations. That leaves two resistors that are in [...]

If your scanned work refers to circuit 5, I don't understand what you calculated where. Please write it down here, including explanations what you are doing.
 
Scan 7 showed Circuit 5. I broke it down because R3 and R4 were in series as well as R1 and R2. Then R34 and R12 were in parallel. This created R1234. I calculated the equivalent reistance of R1234 first by using the series equation and adding the resistances together. Then I did 1/R1234 to calculate the equivalent resistance. For the battery's current I used the voltage divided by the equivalent resistance. Here's where I don't understnad R1, R2, R3 and R4. how do I calculate the restiantces and currents. I12=V12/R12. I got I12=I1=I2

Then for V1=I1R1. Then I calculated V2 from the current I12xR2. Same with V3. Could someone check my work?

I need to find all the calculations for Circuits 5-8.
 
Dhooy7 said:
Here's where I don't understnad R1, R2, R3 and R4. how do I calculate the restiantces and currents. I12=V12/R12. I got I12=I1=I2
It looks to me that you are given the values of the resistances:
Dhooy7 said:
I can only use the resistances of each resistor and the voltage of the battery.

R1=10.44
R2=10.36
R3=10.12
R4=10.13

Vbatt=5.85 V

Aren't they the R1, R2,...R4 values above, presumably in Ohms?

So perhaps you mean that you want to calculate the potential drop (voltage ) across each resistor and the current through each resistor?

You should have covered the basics of serial and parallel connections and what they imply for voltages and currents. That is, parallel components share the same potential drop but may have different currents, whereas series-connected components all have the same current but may have different potential drops on each component.
 
I have to check on this. I'm not sure if it is each resistor's current and resistance or current and voltage. We have the resistances but not sure if we have to compare measured and calculated resistances. I am pretty sure I was mistaken. We need the current and Voltages of each resistor not restances.
 
Your work looks correct.
I think you are just confused about what you are supposed to do and not how to do it.
Your physics and calculations are fine.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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