Recent content by supersunshine

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    Rate of current changing through an inductor

    Homework Statement At time t=0 a 45V potential difference is applied to the leads of a coil with inductance L=50 mH and resistance R=180 ohm. At what rate is the current through the coil increasing at t=1.2ms? Homework Equations 1) L=EMF/ (di/dt) 2) L=N(flux)/i 3)emf=iR The Attempt...
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    How Is EMF Induced in a Shrinking Square Loop?

    Homework Statement "A square loop of wire is held in a uniform magnetic field of .24 T directed perpendicular to the plane of the loop. The length of each side of the square is decreasing at a constant ratee of 5.0 cm/s. What is the emf induced in the loop when the length 12 cm...
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    Electric potential, off by a factor of 1/2

    thanks, i added change in KE+ change in PE and got 3/2, but i think i should have subtracted KE-PE and 1/2 kQq(1/r1-1/r2)
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    Electric potential, off by a factor of 1/2

    Hi, thanks for the tip. I set Fcent=Felec= mv^2/r=kQq/r...solving for v^2 I got V[SIZE="1"]1^2= kQq/mr[SIZE="1"]1 and V[SIZE="1"]2^2=kQq/mr[SIZE="1"]2. I pluged these values into the equation KE1+U1=KE2+U2= Wext and got wext= 3KQq/2 (r2-r1/r1r2). Where am I going wrong?
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    Electric potential, off by a factor of 1/2

    Homework Statement "A particle of positive charge Q is fixed at point p. A second particle of mass m and negative charge -q moves at a constant speed in a circle of radius r1 centered at P. Derive an expression for the work that must be done by an external agent on the second particle to...
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    Work to create a square of charges

    hi, i'm completely stuck on this problem Homework Statement the problem asks for an expression for the work required to create a square charge configuration starting with the charges starting at infinity: each side is length a. on the top left corner the charge is +q, top right: -q...
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