Physics 35 Coulomb's Law (4 of 8) Example 1 (Challenging Problems)

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  • Опубліковано 8 січ 2025

КОМЕНТАРІ • 126

  • @MichelvanBiezen
    @MichelvanBiezen  10 років тому +8

    Off course you would need to have a numerical value for the right side of the equation first.
    Then you would want to do it numerically. Try a value, see how close you get, then pick a closer value etc.

  • @vincentesperanza4736
    @vincentesperanza4736 7 років тому +16

    How can you get the angle theta given those variables. You used sine and cosine functions in the last equation, still u need to simplify further to get a single trigonometric function and do the inverse trig function to get the theta alone :)

    • @iridium8562
      @iridium8562 4 роки тому +1

      You will need to solve it numerically

  • @digitaldrreamer
    @digitaldrreamer 6 місяців тому +3

    Thanks. From Nigeria 🙃
    I'm glad I found your channel

    • @MichelvanBiezen
      @MichelvanBiezen  6 місяців тому +2

      You are welcome. We are glad you found our channel as well. Welcome to the channel.

  • @ericlongteaches
    @ericlongteaches Рік тому +2

    how did 4 come from k? isn't k supposed to be 9x10^9
    5:47

  • @veluri557
    @veluri557 2 роки тому +2

    Wish my teacher was explaining stuff like you mr. Thanks endlessly

  • @jcmick8430
    @jcmick8430 3 роки тому +1

    this is way more challenging than physics 104 will call for, and still I'm glad I watched this

    • @MichelvanBiezen
      @MichelvanBiezen  3 роки тому +2

      Looking at the more challenging problems often helps us with the basic concepts.

  • @shawnscientifica6689
    @shawnscientifica6689 6 років тому +4

    This problem would defeat me because I assumed it is asking me to solve for theta in terms of those variables which requires using trigonometric identities and reversing the function to get the angle in pure form.

  • @magsanimation1
    @magsanimation1 4 місяці тому

    3:50 sorry to ask but didn't you make an error placing the mg in the denominator?😢

  • @AH-pb8cm
    @AH-pb8cm 7 років тому +6

    Amazing video Mr. Van Biezen! Thank you so much!

  • @marylovet
    @marylovet 5 років тому

    getting theta by using small angle approximation (as d approaches 0, cos d=1 and sin d = d). Therefore the final answer is θ= (q^2/((epsilon_0)*pi*16*l^2*m*g))^(1/3)

  • @manavparmar1807
    @manavparmar1807 6 років тому +4

    i from india and you are doing a right for student like me and others thank you sir , you are genius

  • @NjabuloMabaso-lz5ci
    @NjabuloMabaso-lz5ci 3 місяці тому

    Thank you sir, hope you live a long prosperous life. I wish you nothing but the best❤

  • @Exoudar
    @Exoudar 5 років тому +1

    At 2:40, would you please explain why the sum of the three forces is equal to 0?

    • @MichelvanBiezen
      @MichelvanBiezen  5 років тому +1

      If the sum of the forces add up to zero, then there is no net force, which means that the particles will not accelerate. Consequently, if the particles are not accelerating, then there is no net force and therefore the forces will add up to zero.

    • @Exoudar
      @Exoudar 5 років тому +1

      @@MichelvanBiezen Thanks !

  • @anasghaffar7837
    @anasghaffar7837 4 роки тому +1

    Couldn't you just shift tangent to the right to find theta and so we'll have theta equals arc tangent of the whole thing in the end?

  • @valeriereid2337
    @valeriereid2337 Рік тому +2

    Excellent explanation. Thank you so very much.

  • @shivaychoudhary5935
    @shivaychoudhary5935 6 років тому

    Amazing teaching over their sir.thank u sooo much .greetings from India

  • @DIPANKARDAS-tx2cl
    @DIPANKARDAS-tx2cl 6 років тому +3

    Please make videos on hard problems on electricity

  • @tiannamamo5862
    @tiannamamo5862 6 років тому +2

    Thanks for this. Makes so much sense now. You are awesome

  • @mjmeternal2696
    @mjmeternal2696 4 роки тому +2

    Dear Sir. I would use a small-angle approximation to find the final answer. So the angle = (A/B)^(1/3)

    • @mathlover2299
      @mathlover2299 2 роки тому

      Why? This is a more general answer.

  • @educhan3909
    @educhan3909 2 роки тому +4

    I don't understand. where did 1/4piepsilon came from?. I found in the internet it said, "it's equal to coulomb constant." But why is that?

    • @MichelvanBiezen
      @MichelvanBiezen  2 роки тому +4

      That is correct. 1 /4 pi epsilon is indeed the coulomb constant. epsilon sub knot is the permittivity of free space. It is experimentally determined.

  • @gauravaiims-d8452
    @gauravaiims-d8452 4 роки тому

    I'm from India 🇮🇳
    You cleared my very important doubts.
    Thanks 😊😊❤

  • @dr.akash_deep
    @dr.akash_deep 5 років тому +1

    Love from 🇮🇳 (Indian)

  • @ammarshazly2141
    @ammarshazly2141 2 роки тому +1

    why tension isn't resolved on both axes against the repulsive force or the gravitational force?

    • @MichelvanBiezen
      @MichelvanBiezen  2 роки тому +1

      Not sure what you mean by "both axes". Are you asking why we don't calculate the tension in both strings? If that is the question? If yes, they are perfectly symmetric so the answer is valid for both strings.

  • @labyrinthminds_
    @labyrinthminds_ 8 років тому +2

    You, kind sir, just earned a subscriber! Thank you so much for your videos!

  • @mynameismichael97
    @mynameismichael97 8 років тому +1

    Hey, I just wanted to know why you are able to make the triangle from the forces and also why that theta is equal to the angle we are looking for? Thanks!

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому +4

      Since the two charged objects are in static equilibrium (because they are not moving), the net force on each must be zero. (Newton's second law, F = ma). If there is no net force then the sum of all the forces acting on each charged object must be zero. Hence the triangles. (This is a very typical solution involving vectors adding up to zero).

  • @RyanJumarPantoja
    @RyanJumarPantoja 6 років тому +2

    sir if i may ask im not good in trigonometry i want to know how can you compute for the angle in your equation sin^3 theta / cos theta... thanks sir...

    • @MoMocrafterable
      @MoMocrafterable 5 років тому

      Ryan Jumar Pantoja no problem. You could write the left side as sin^2 theta * tan theta. The. Divide both sides by sin theta tan theta, then take arc sin of both sides to isolate theta. 😉 I absolutely love trig

  • @fernandadelgado2902
    @fernandadelgado2902 7 років тому +2

    hi! this might be a silly question but how did end up with 4d^2? isn't 4d only ?? I really don't see the algebra done behind it

  • @victoriawu6551
    @victoriawu6551 7 років тому +3

    Thank you so much for the clear, easily understood lecture.

  • @mcaljojoromat1597
    @mcaljojoromat1597 8 років тому +1

    3 charge particles Q1= -5 micro C, Q2= 5micro C, Q3= -5micro C, assume that Q1 is at the origin and Q3 is right next to Q1, Q2 is at the top between Q1 and Q3. Angle Q2 Q3 Q1 = 20 degrees and angle Q3 Q1 Q2 =40 degrees. HOW MUCH WORK MUST BE DONE TO MOVE Q2 FROM ITS POSITION TO HAFLWAY SITUATED BETWEEN Q2 AND Q3.
    Sir pls help me with this problem, i can simply get the force for each charge affect by the other charges but i really don't know how to get the WORK.

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому

      This video (and the one following this one) may help you figure it out. Physics - Electrical Potential and Electrical Potential Energy (6 of 6) ua-cam.com/video/y8vGuA6k6so/v-deo.html&index=6&list=PLX2gX-ftPVXXFqBJixIbQcyXZD6kQnAQH

    • @mcaljojoromat1597
      @mcaljojoromat1597 8 років тому

      done watching those videos sir ,over and over,still no idea in solving it. i dont know what formula to use in getting the WORK. pls help me sir.

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому

      When you place a charge near another set of charges, the work done for each additional charge is equal to the sum of potential energy gained or lost by being close to another set of charges. Change in energy = k * Q1* Q2 / R. Q1 is the charge already there and Q2 is the charge added. You have to calculate that for each Q1 as there could be multiple Q1 charges already present.

  • @stephaniegarcia8557
    @stephaniegarcia8557 4 роки тому +1

    What would happen if the charges were opposites of each other? Would the calculations be different?

    • @MichelvanBiezen
      @MichelvanBiezen  4 роки тому +3

      Then the objects would attract and there would be zero distance between the objects.

    • @stephaniegarcia8557
      @stephaniegarcia8557 4 роки тому +1

      @@MichelvanBiezen Got it, Thanks!

  • @sandeepbadiganti
    @sandeepbadiganti 7 років тому +3

    thank u sir.. its amazing

  • @RyanJumarPantoja
    @RyanJumarPantoja 6 років тому +1

    amazing... nice lecture sir...

  • @_avenger9709
    @_avenger9709 8 років тому

    Couldn't you also solve this problem by adding the components of the forces like we do in regular static problems instead of making the triangle? I tried it and I got sin(theta)/cos(theta) = (mg*4pi*epsilonR^2)/q^2. So basically I got what you had, but my answer is flipped.

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому +1

      There are usually multiple ways in which problems can be solved. The "triangle method" is a method that is used in many applications and very quick and useful.

  • @rmuchala
    @rmuchala 8 років тому +2

    could you please list problems 4- 8 on ilecture online?

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому +3

      We still need to link a number of videos to our web site. Thanks for the reminder.

    • @rmuchala
      @rmuchala 7 років тому +1

      Please let me know if you need any help, I am available to help. I am a also web programmer. Thank you for the videos excellent explanation.

  • @SandeepsPercussion
    @SandeepsPercussion 10 років тому

    Hey, I am somehow not able to solve for thetha...i tried breaking up sin^3 thetha into sin^2 thetha and sin thetha but it didn't work out. Can you plz help me out? Thanks :)

  • @phoenix2464
    @phoenix2464 6 років тому +1

    Hello, you forgot to add these videos to ilectureonline

    • @MichelvanBiezen
      @MichelvanBiezen  6 років тому +2

      Thanks for letting us know. :)

    • @admir_mohammadi
      @admir_mohammadi 3 роки тому

      @@MichelvanBiezen Hello sir.I think you don`t added yet.

  • @evanlouder2961
    @evanlouder2961 9 років тому +1

    Could u please make some more challenging problems. Thank you.

  • @monkeyx998
    @monkeyx998 7 років тому +3

    Excellent videos, greetings from Chile!

  • @zewditukergo7951
    @zewditukergo7951 8 місяців тому +1

    Thank you so much❤

  • @tsoojbaterdene7793
    @tsoojbaterdene7793 3 роки тому +1

    In this case,How to find tension in the rope?

    • @MichelvanBiezen
      @MichelvanBiezen  3 роки тому +1

      The mass and quantity of charge are independent. The mass represents how much material is in each object.

  • @8a1nivetha14
    @8a1nivetha14 5 років тому +1

    Awesome sir

  • @waleh342
    @waleh342 6 років тому +1

    Thank you so much for this.

  • @keithfrancisco4266
    @keithfrancisco4266 8 років тому +1

    Hi sir, I would like to ask you about how to solve charges in an oblique triangle. Is there another way of solving it without using the cosine law? thank you.

  • @anasghaffar7837
    @anasghaffar7837 4 роки тому +1

    Also if you could solve it for theta it would be better

    • @DANIELDALLAS_MATHs
      @DANIELDALLAS_MATHs 4 роки тому

      You are right man! Just another angle of consideration

  • @Hanif-yc6jj
    @Hanif-yc6jj 9 років тому

    how about the tension ?

  • @syedafaqkhan1830
    @syedafaqkhan1830 5 років тому

    thank you soo much you are really great

  • @he3nha3oha3o4
    @he3nha3oha3o4 3 роки тому +2

    Thank you sir

  • @Sofialovesmath
    @Sofialovesmath 4 роки тому +1

    Thank you so much

  • @vidyarthv9735
    @vidyarthv9735 8 років тому

    What is the tension when the system is taken deep into space ??

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому +1

      +ViDdU vidyarth
      Then the distance between them would be 2L and you would use Coulomb's law to calculate the force ( = tension) between them.

    • @2RiPlay
      @2RiPlay 8 років тому

      Because there would be no weight (no gravity) and only the charge forces acting to cause tension in the string. Nice.

  • @hunters9048
    @hunters9048 7 років тому +1

    Sir please tell me where i can study my maths

  • @MuhonaKahimuee
    @MuhonaKahimuee 10 місяців тому +1

    What if the is no gravity

    • @MichelvanBiezen
      @MichelvanBiezen  10 місяців тому +1

      Without gravity the strings would be horizontal.

  • @guilhermedemedeiros6911
    @guilhermedemedeiros6911 2 роки тому +1

    Thank you so much!

  • @raulrodriguez9307
    @raulrodriguez9307 8 років тому

    I have a question. Why the 16pieEsubnot0????

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому +1

      k = 1/(4 * pi * epsilon sub knot)

    • @raulrodriguez9307
      @raulrodriguez9307 8 років тому

      +Michel van Biezen Is it like an established principle or law? That K equals that Dr. Biezen?

    • @MichelvanBiezen
      @MichelvanBiezen  8 років тому

      k is an experimentally derived constant of nature. It is related to the properties of the fabric of space, also known as the permittivity of free space

  • @shyamfrancis9350
    @shyamfrancis9350 7 років тому +1

    You are awesome

  • @manavparmar1807
    @manavparmar1807 6 років тому +1

    nice sir

  • @sarjeraopatil8088
    @sarjeraopatil8088 4 роки тому +2

    Such questions are very much easy for 12th students from India

    • @rkusuma6852
      @rkusuma6852 Рік тому

      This a very important comment, and certainly contributes much in this context. ;)

  • @marvelphycko2926
    @marvelphycko2926 4 роки тому +2

    Any NCERT here????

  • @dimple4328
    @dimple4328 4 роки тому

    Sir why do we use 2d^2

    • @admir_mohammadi
      @admir_mohammadi 3 роки тому

      we use (2d)^2 because its the distance of two charges.

  • @hennanoor6346
    @hennanoor6346 2 роки тому +1

    a legend

  • @AniketMandal12
    @AniketMandal12 5 років тому +1

    Thank u sir

  • @youretard1203
    @youretard1203 8 років тому

    simple problems

  • @bull3asaur168
    @bull3asaur168 4 роки тому

    I thought we are going to find Q=...... I was afraid

  • @doga4069
    @doga4069 6 років тому +1

    wow i blinked

  • @TheZagros3000
    @TheZagros3000 6 років тому +1

    Sir, I get answer = (q^2/2π £o mgL^2)^1/3 but its different from yours.

    • @MichelvanBiezen
      @MichelvanBiezen  6 років тому +1

      Did you work it out the same way?

    • @TheZagros3000
      @TheZagros3000 6 років тому +1

      @@MichelvanBiezen yes sir, I followed your solution for a similar problem however in this problem I am to assume that the angle a is small(meaning sin a=a).

    • @MichelvanBiezen
      @MichelvanBiezen  6 років тому +1

      Why don't you plug in some numerical values and see if the 2 answers are close?

  • @LearnWithFardin
    @LearnWithFardin 3 роки тому +1

    Wow!

  • @frankjeromebbascon
    @frankjeromebbascon Рік тому +1

    lato lato

  • @ElifArslan-l9g
    @ElifArslan-l9g 3 роки тому

  • @tsoojbaterdene7793
    @tsoojbaterdene7793 3 роки тому

    In this case,How to find tension in the rope?

    • @MichelvanBiezen
      @MichelvanBiezen  3 роки тому

      Since we know the Coulomb force and mg, we use the Pythagorean theorem (or sin, cos, or tan).

    • @tsoojbaterdene7793
      @tsoojbaterdene7793 3 роки тому

      But mass is unknown,Sir!