Electric potential energy of charges | Physics | Khan Academy
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- Опубликовано: 28 июл 2016
- In this video David explains how to find the electric potential energy for a system of charges and solves an example problem to find the speed of moving charges.
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Hey khan, to be honest,the level of clarity,depth of understanding,way of explanation are simply awesome man..your videos are mind blowing..My humble request to you "PLEASE DONT STOP ANYWHERE"..keep uploading more and more videos in physics
Its david
Apologies to Sal for this comment, even though it is intended, if anything, as constructive criticism - but the way David explains things is so much clearer. He does not feel the need to fill in every bit of time with words (which I'm sorry to say oftentimes comes off as rambling with Sal), but speaks eloquently, letting us take it in. Also I can tell the graphics are cleaner as well, I'm sure Sal can implement this. But the slower and better organised mode of speaking, the clear explanations, for me they make David preferable for me. Please make more videos
@luizsaunders
It's not like it's personal, dude! Plus... You're *_correct,_* lol. Or at the very least, I agree... 😏
This is guy is SO GOOD at explaining.
How is no one talking about his ability to draw perfect arrows?? ( well, obviously apart from how good he teaches)
Because the program lets him draw them straight 💀
I really liked how he explained what each of the values meant. Keep up the good work!
This is so helpful!! Thank you so much 😊
I m feeling sad for the channel as it is theee best channel for physics but always underrated.......I have no words how much he has helped me in understanding concepts. He always takes the exact doubts which arises in my mind in his videos...... Amazing Channel if anyone want to study seriously......
amazing...
Nobel prize in teaching
"This is physics so they don't care" lololololol
Thanks David, nice teaching
I really loved this video because the speaker is so funny. ^^
thank you so much!!!!!
Loved it.
2:12 Where's the link? It's not there in the description -_-
www.khanacademy.org/science/physics/electric-charge-electric-force-and-voltage/electric-potential-voltage/v/electric-potential-energy-part-2-involves-calculus?modal=1
thanks for saving my grades
Thank you so muchh
isnt k the coulomb constant and not the electric constant?
nice
Even though I'm watching this 5 years later and I still think that David's a wonderful teacher, I can't help but notice that when I multiply the values in the first problem he solved that I got different values from what he got. Because where he got 2.4, I got 5.4 and where he got 0.6, I got 1.35 :(
It's either my calculator's broken or I prolly missed something
Can someone please explain :(
i think david confused electric constant with coulomb constant (the correct constant)
Thank You!
thanks for the explanation, but I am still confused about something:
in a series circuit made of a battery/cell providing an electromotive force of 9 V, and a bulb, the electrons give the bulb all the energy they are carrying which is 9 V, so how do they continue moving after leaving the bulb if they lost all their energy?
The electrons are not giving up all their energy! If you do introduce a sufficiently large number of bulbs in the series circuit, you can build up your resistance high enough that all the energy is "given up" (loosely speaking) and there is no flow (no light)
Need derivation video link and also if you can make it available in Hindi on channel "Khan Academy India"
What if the masses weren't the same? would you need more information to solve for their velocities?
You would just write out two separate kinetic energy terms with two different masses and add them
Use conservation of momentum
@Nick Baroni but wouldn't you have two unknown variables then? v1 and v2?
Their momentums are equal and opposite, but their masses are different. Since you know their masses and the change in potential energy, you can solve for the magnitude of the momentum, p, by doing the following:
(1/2) (p^2 / m_1) + (1/2) (p^2 / m_2) = change in kinetic energy = -1 * change in potential energy
Solve for p. Then solve for v_1 by dividing p by m_1. If you can do that, you can figure out v_2 as well.
In Current and Electricity what is the higher potential... Guys this thing is messing me soo much..
I don't know why but i can simply get this thing clear.. My Exams are just around the corner.
I have Questions of which I need some simple answers.
1.What basically is the electricity??
2.Do electrons flow from Positive terminal to the negative terminal or from the negative terminal to the positive terminal.
3. What does actually flow: Protons or Electrons?
Please reply to me...
Thank you in advance.
I know maybe you dont need this anymore but here it goes: 1. Electricity is a flow of electrons, generally passing through a circuit, the electrons have electric potential energy and they use it to get to the other side, thats why you can connect a device to the circuit and use some of that energy.
2. Electrons always travel from the negative terminal (its negative because it has electrons) to the positive terminal because opposite charges attract each other (thats why the electrons have potential energy).
3. Protons never flow because they stay at the atom's nucleus. Electrons always flow: an object has negative charge when it has more electrons than protons and it is positively charge when it has less electrons than protons. This do NOT mean protons traveled to this body but instead the body's electrons moved away (for example to a more positive object), leaving the object with a normal number of protons a low number of electrons (thus having more electrons than protons and therefore being positively charged).
Hope this helped
femitrs999 your first answer impressed me dude👍👍👍
😂😂😂😂😂great n funny man
if their masses would've been different their velocities would of also been different?
But how do you find one of the speeds using conservation of energy if the masses aren't equal?
Just take individual kinectic energies of the different masses.
What does a negative potential energy mean?
It means instead of going to a state with higher energy, ie potential energy converted to kinetic, your objects want to loose energy.
An infinite separation of charges has no potential energy. Zero. If the charges attract each other, the potential energy must be used as they pull toward each other, and so the potential energy is made negative. The amount of energy you can release from these charges is limited by how close they can get to each other. The closer they can get, the "more negative" you can make the potential energy.
@@ayoutubechannelname Thanks man, I had the same question and everything clicked when I read this comment.
what if the masses were different, use energy conservation and conservation of linear momentum in the horizontal direction to get the 2nd relationship between velocities. 0 = m1.v1 + (-m2.v2)
3:39 isn't the unit for electric potential energy Volts?
what if the masses werent just 1kg then how would i sort out the calulation. for example 1.67x10^-27kg the mass of a proton
figured it out yet?
@@rkusuma6852 nope I switched programs. gl friend
I'm still a bit confused as to why the speeds are the same :(
Both charges have zero momentum initially. So the whole system has a total momentum of zero. When the charges accelerate their opposite ways, they must have equal but opposite momentum for the system to still have zero total momentum. Both charges have the same mass, so their final velocities must be equal but opposite. The velocities are equal in magnitude, despite being in opposite direction, so the speeds are the same.
the force exerted by q1 on q2 is the same as the force exerted by q2 on q1. From Coulomb law F= kQ1Q2/r^2. If they have the same force and same mass, they have the same acceleration. If the acceleration is the same, the speed will be the same.
*_Summary Of The Video :-_*
*Electric Potential Energy*
*Definition* - The amount of work done in assembling the charges at their location by bringing them from infinity.
* A single charge can not have any potential energy.
* We need at least two charges to have potential energy at all.
* SI UNIT - Joule.
* Potential energy is a Scalar Quantity.
So basically using signs in this equation only gives better understanding and does not affect the answer, Making it of no use eh