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PLEASE I NEED HELP I BEG YOU!!! PLSPLSPLSPLS 🙏 (1 Viewer)

Gods_Spear

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If the voltage is travelling from the + to the - would that not lead to a positive spike? Im fine with the second spike being bigger, it makes sense but this may be where my confusion lies
 

sainzsgf

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lol idk this is the only stuff im alr at in the syllabus so hopefully im correct 😬 im so fucked for mod 7 and 8 rn 😢
i did a question kinda similar to this yesterday with a solenoid and a magnet and the other end of the solenoid did turn into a north pole like with the same set up as this question but idk maybe im getting confused
 

Gods_Spear

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i did a question kinda similar to this yesterday with a solenoid and a magnet and the other end of the solenoid did turn into a north pole like with the same set up as this question but idk maybe im getting confused
Because usually with these sort of questions the magnet entering the solenoid has the north side at the front not the south side. At least thats what I see, but I got the question wrong
 

igor9

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If the voltage is travelling from the + to the - would that not lead to a positive spike? Im fine with the second spike being bigger, it makes sense but this may be where my confusion lies
tbh i am not too familiar with the data logger part, but i stand by the south pole being created at the top, because initially the solenoid will try oppose the change in flux and hence try push the magnet out, and so since the South pole of the magnet is at the bottom, it should create a south pole at the top of the solenoid to oppose it right? and then when it leaves it will try attract it and then create a south pole at the bottom of the solenoid.
 

Gods_Spear

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tbh i am not too familiar with the data logger part, but i stand by the south pole being created at the top, because initially the solenoid will try oppose the change in flux and hence try push the magnet out, and so since the South pole of the magnet is at the bottom, it should create a south pole at the top of the solenoid to oppose it right? and then when it leaves it will try attract it and then create a south pole at the bottom of the solenoid.
Yeah I agree with the south pole at the top of the solenoid
 

igor9

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also this change in where the south pole is definitely explains the change in direction of the voltage on the graph, but abt the data logger, I kinda just guessed how it worked based on the shape of the graph.
 

sainzsgf

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Because usually with these sort of questions the magnet entering the solenoid has the north side at the front not the south side. At least thats what I see, but I got the question wrong
oh yes yes mb. sorry didn't mean to get u confused day before the exam
 

igor9

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Yeah I agree with the south pole at the top of the solenoid
yea it has to be, since whatever the magnet is doing it will act opposite to it. so if it is trying to enter, it will say gtfo, and if it tries leave it will say get back in.
 

igor9

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and does my assumption abt force of gravity being greater/acceleration as it leaves make sense, coz if there is more acceleration or force, then the emf has to be greater to oppose that force, so that is why the amplitude of the second part of the graph is greater.
 

Gods_Spear

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Exactly, so it must be the data logger that has some funny business that I dont understand
and does my assumption abt force of gravity being greater/acceleration as it leaves make sense, coz if there is more acceleration or force, then the emf has to be greater to oppose that force, so that is why the amplitude of the second part of the graph is greater.
Yeah its travelling faster so it has greater change in flux
 

penguinzombie

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im confused how do you even know if it would be positive or negative, i got my fingers coiling into the page for the current, but how does that mean anything, why is the second peak less then the first one. I am so cooked for tomorrow
 

FudiddidoAdrian

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i think ur correct, the top of the solenoid would be south to repel the magnet as it enters but as you can see from the data logger the solenoid is originally north, which means that south indicates a negative curve?? idk
 

FudiddidoAdrian

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i think ur correct, the top of the solenoid would be south to repel the magnet as it enters but as you can see from the data logger the solenoid is originally north, which means that south indicates a negative curve?? idk
the data logger shows you that the top of solenoid is north(+) initially, which means that when magnet enters it will turn into south pole to repel, thus making the curve negative as it assumes the solenoid is initially north if that makes sense.
 

Gods_Spear

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Could you just explain why the amplitude is like that pls :)
This is a hard question so dont worry to much, the amplitude is like that because the induced current is equal to the rate of change of flux, when it originally enters it induces a certain amount of current, when it is in the middle it has no effect because it cancels itself out. However while it was falling it was accelerating, meaning that it falls out of the bottom of the solenoid faster then it entered, which if you look at faradays formula means a smaller value for time for the same amount of flux change indicating that there will be a greater emf. Still confused about the direction
 

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