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    Determine the value of the inductance ?

    Thanks again for the clarification. Hmmmm... why tan(theta) why not cos(theta) ...?? You have answered same question before and i want to understand it 2 .. https://www.physicsforums.com/showthread.php?t=328964 check the link . If i was answering the question i would say the...
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    yup , i have done it. thanks a lot NvN. all credit goes to u . thanks a ton.
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    Determine the value of the inductance ?

    wow ..thx a ton rl.bhat. whould u tell what expression must i use if the question says the voltage across the inductor ?? and how did you get Vc-Vl why it not Vl-Vc ?? thanks again ..
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    Problem involving the equation of a plane

    Here is the problem n = -3i + 3j + 9k it must be -9k Not +9k
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    Average force

    what does acceleration equal .. ?? Change in what / change in what ... ?? Find the initial and final velocities and change in time and u r done. ^^
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    The current in the circuit ?

    The current in the circuit ...?? Homework Statement An AC voltage of the form V = Vmax sin 2*pi*f*t , with frequency 22 Hz and maximum voltage 763 V, is applied across a 17 W light bulb. When the voltage is first applied. a) what is the current through the circuit? Three Choices ...
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    Determine the value of the inductance ?

    Determine the value of the inductance ...?? Homework Statement Consider a series RLC circuit. The applied voltage has a maximum value of 210 V and oscillates at a frequency of 76 Hz. The circuit contains an inductor whose inductance can be varied, a 900 ohm resistor, and a 1 μF...
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    Ok , i have read the textbook and found the difference b/w the Ip Or J and I I found that the rectangular second moment of area I = pi*(r4)/4 Thanks NvN. Now i have one more question how to find T the torque here : \tauxy = = + T*c / I T = ?? Thanks Pongo38 for the respond i...
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    Finding the inductance of a coil

    Ideasrule told you that ... B=2.6 mT when I=3.8 A ,,,,,, So find L the length of the solenoid by this equstion : B=μ0*N*I/L Where , B = 2.6e-3 T N = 30 turns I = 3.8 A So L = ? Then substitute the value of L in this equation to find the Inductance of the Solenoid : L...
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    Magnetic field between two parallel wires

    I think that it is correct for anti-parallel case. 30 A for each wire.
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    Ok i will not change anything . Hmm , Why it is divided by 4 what is the difference b/w this and J When i calculated J i used R the radius of the shaft not the diameter. Here you divided by 4 which means to me that r here represents the diameter not the radius... am i right ??
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    http://img268.imageshack.us/img268/1417/1copyr.jpg [Broken] Ok, I switched the z & y axes in my diagram but why u did that ...?? What about the location of stresses are they going to stay on there old localtion after switching...?? (( In this case I think that there woulb no more σy or...
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    Simple question about the power generated by an elevator motor

    thx for ur responding. So shall i take the nearest answer which is 500 Kg or what ..??
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    The final Step Find the principal stresses and using the given factor of safety and the yield stress of steel calculate the allowable Load. I think that ,, σx = 0 σy = + M*c / Ip , M = 1.1228e5 *P , c = 0.009525 m , Ip = 1.2929e-8 \tauxy = + T*c / Ip , T = ?? Now...
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    Simple question about the power generated by an elevator motor

    Homework Statement The motor of an elevator generates 12000 Watts of power when moving the elevator at constant speed of 2 m/s.what is the mass of elevator in kg ...?? There are 5 options for the answer. a) 500 Kg b) 400 Kg c) 300 Kg d) 240 Kg e) 200 Kg Homework...
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    Now i want to move to step 3. http://img14.imageshack.us/img14/7660/1copyjm.jpg [Broken] Determine the stress state at the wall (location of the maximum bending stress and torsional stress) First of all , Did I locate the stresses correctly with directions , second how to find the...
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    Ooops i think that I wrote Ig by mistake.Sorry So now Ip is the same found in the 1st step right ..?? Ok the moment now must = 6 * P In SI units = 0.1524 * P So σBending max = 0.1524 * P * 0.009525 / 1.2929e-8 σBending max = 1.1228e5 *P N/m2 Thats it second step done ...
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    Alright then let's move to the second step . Calculate the maximum bending stress in the circular bar. σBending max = M*c / Ip where M is the bending moment. c is the maximum vertical distance away from the N.A ( Neutral Axis) Ip is the moment of inertia. I found c to be the...
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    Mechanics Question : Maximum Load needed ? Urgent Please Help

    Mechanics Question : Maximum Load needed ?? Urgent Please Help Homework Statement http://img694.imageshack.us/img694/5462/66814773.jpg [Broken] A new steel bracket was designed to support various loads being hung from the end. The designer would like to know the largest load that can be...
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    Maximum induced emf with 2 Solenoids

    thanks for response hmmm.. ok there is no need to substract one from another, how do i find the flux associated with the outer one ? Do i have to use the inner magnetic field to find the outer flux ?? Or Do i have to use the inner flux to find the outer flux and how ??
  21. F

    Maximum induced emf with 2 Solenoids

    Please anyone who can point me to the right direction ...
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    Maximum induced emf with 2 Solenoids

    Homework Statement A 3 m long large coil with a radius of 15.7 cm and 130 turns surrounds a 7.2 m long solenoid with a radius of 5.7 cm and 4700 turns. The current in the solenoid changes as I=I_0 sin (2\pi f t) where I0= 30 A and f=60 Hz.Inside solenoid has 4700 turns and outside coil has...
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    Magnetic Field , Self-inductance & energy Question

    Finally i got the right answer . thanks ideasrule for the help . what i have done to solve this problem : The induced emf for the small solenoid is given by Faraday's Law of induction http://img228.imageshack.us/img228/9731/emf.png [Broken] emf = -N2 dφ/dt = -N2 A2dB/dt =...
  24. F

    Circuit problem

    hi chronicals .. I hope this topic will help you https://www.physicsforums.com/showthread.php?t=248637 Please check it
  25. F

    Magnetic Field , Self-inductance & energy Question

    part d) the emf needed for the small solenoid inside = -n (d[phi]/d[time]) n = 32 turns d[time] = 5 seconds d[phi] = B*A B = μ0 * N * I / L , μ0 is given , N = 323 turns , I = 44 A , L = 0.4 m A = π r^2 , r = 0.002 m after finding d[phi] to be = 5.611e-7 T emf = -...
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    Magnetic Field , Self-inductance & energy Question

    hmmm ... i answered the first three parts correctly. i missed a little informations in those equations above , that's why i could not answer them. for part a) i used B = μ0 * N * I i forgot the length L so it will become like this B = μ0 * N * I / L for part b ) self inductance...
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    Magnetic Field , Self-inductance & energy Question

    Homework Statement Given: μ0 = 4 π x10−7 T.m/A. An air-core circular solenoid is shown in the figure below. A current of 22 A is establishedin the wire which makes up this solenoid. http://img412.imageshack.us/i/81565602.jpg/ a) What is the magnetic field at its center? [[ Answer...
  28. F

    Maximum Induced Emf

    thanks kuruman for eplanation. I understood now why i couldn't find a maximum value when deriving the equation. thanks a lot man .
  29. F

    Maximum Induced Emf

    Wow , thanks kuruman for the help , it is right , when time is zero i get a maximum emf E. but i have a question ,,, can i find the maximum by deravatives and how and when to use ? thx in advance for all who are helping us ... ^^
  30. F

    Capacitor Q=CV Problem

    (a) The switch S is open. The top two capacitors are in series: Ctop = 1/(1/3+1/6) = 2 μF, and the bottom two are also in series: Cbot = 1/(1/6 + 1/3) = 2 μF. The top and bottom capacitors are in parallel: Ceq = Ctop + Cbot = 4 μF. The total charge on the capacitors is: Qtot = CeqVab = 840 μC...
  31. F

    Maximum Induced Emf

    Homework Statement A flat loop of wire of area 15.7 cm2 and 1.09 turns is perpendicular to a magnetic field whose magnitude decays in time according to B = 0.5 e−t/7. What is the maximum induced emf? Answer in units of V. Homework Equations \epsilon= \Delta\PhiB/\Deltat \epsilon=...
  32. F

    Again an electric potential question ?

    Wow nice Job Friend , its absolutly right ^^ thank U very much ^^
  33. F

    Again an electric potential question ?

    Aha , i get it now. I will submitt the answer & i am sure it will be correct this time , I'll be right back in minutes ^^ THx again Boss ^^ Really appreciate Ur help !
  34. F

    Again an electric potential question ?

    thx 4 clarifying about the potential ^^ But is'nt taking an integral from 5 to infinity will give me infinity and when i multiply infinity with E i will get also infinity ? In case what u r saying is correct what is the value of r then ?? Is it the distance from point p to x1 or to...
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    Please help Easy motion question

    Hi kevinli , welcome to PF ^^ first equation (v=a*t) is for Velocity = acceleration * time in units = (m/s²)*(s) = (m/s) which is the SI unit for Velocity ^^ the second one (d=v*t) is for distance = velocity * time in units = (m/s) * (s) = (m) which is also the SI unit for...
  36. F

    Again an electric potential question ?

    The Attempt at a Solution I know that E in this case = kq/[a*(L+a)] a : distance from point P to x2 ( P-x2) L : distance from x1 to x2 ( x2-x1) The denominator = r²= [a*(L+a)] I want Potential V=kq/r r=Sqr(The denominator = r²= [a*(L+a)]) So I just insert the values and got...
  37. F

    Again an electric potential question ?

    Again an electric potential question ? Homework Statement Question # 1 A charge of 7.034 nC is uniformly distributed along the x-axis from −4 m to 4 m. What is the electric potential (relative to zero at infinity) of the point at 5 m on the x-axis? Homework Equations...
  38. F

    Block Sliding Down Ramp

    I have attached the answers for parts A & B .
  39. F

    Am i right on this? Newtons secocd law hw problem

    Yup , U R right ^^ We are here anytime . Feel Free to ask . May God Help U In your Study ^^
  40. F

    How To Find Potential ?

    Alright Tiny Miny Little GoldFish U got it ^^
  41. F

    Block Sliding Down Ramp

    Wooo Wait friend I faced this problem maybe 2 years ago & actually forgot the whole concept of the problem. So please forgive me, try to read it & understand it by yourself & if U stuck In somewhere tell the Members to clear 4 U that part. Sorry Again Captain.
  42. F

    How To Find Potential ?

    Yup , Finally I got right answer Thx a lot Sir. & thanks also for the clarification about grad ^^ Appreciate it. May God Bless You Sir.
  43. F

    Block Sliding Down Ramp

    Hi captain Evil ^^ I faced this problem before and i kept the answer in my Computer ^^ Download it from here : http://www.mediafire.com/download.php?zw11mdmj1kn [Broken] See Ya
  44. F

    Am i right on this? Newtons secocd law hw problem

    Hi mr.coon ^^ & Welcome to the PF Let positive be west and negative be east since they are opposite directions. The forces are 3300 , -940 , -1200 The sum of the forces : 3300-940-1200= 1160 N Newtons law F=ma is used F = 1160 N m = 6800 Kg a = Find It ^^
  45. F

    How To Find Potential ?

    You said if E=kq/r², then E=-gradU , What do u mean by (gradU) & why it is minus ? and here we have E=kqr/R³, so what V must equal now??
  46. F

    How To Find Potential ?

    Hi again sir ^.* Thx a lot for the information and corection that U've posted & I appreciate your help to me Sir. Part C ) MmmMmmm... I actually know an equation for potential which is V=kq/r but I tried it and got wrong answer. I've tried for r once and for R once & still got wrong...
  47. F

    How To Find Potential ?

    Hi Tiny-Tim! Thx 4 Welcoming ^^ Please check my steps of solving this part & tell me if i made a mistake : \phi=\int\vec{E}.d\vec{A} = Int(EdACos[theta]) = Int(EdA) = EA E : Electric Field inside a uniform sphere of charge = KQr/R3 A : Area of the spherical Shell of...
  48. F

    How To Find Potential ?

    How To Find Potential ?? Homework Statement Consider the uniformly charged sphere with radius R = 4.65461 m, Q = 6.66731 μC is the total charge inside the sphere. a) Find the total flux passing through the Gaussian surface (a spherical shell) with ra- dius 2.08762 m. b) Find...
  49. F

    Physics problem help please

    This Question Is been Repeated but with different values . Please Check THis link it may help you . https://www.physicsforums.com/showthread.php?t=254219
  50. F

    Can someone me do this problem

    Emmm ... Question # 1 Should she try to stop, or should she make a run for it ? We have Her driving speed = 50*(1000/3600) m/s Distance From car to traffic Light = 30 m The time that yellow light can stand = 2.0 s Speed = Distance / Time So Time = Distance / Speed t=d/v...
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