Recent content by 123yt

  1. 1

    Calculating Speed of Block with Dielectric in Capacitor

    Homework Statement Consider a horizontal square plate capacitor of area 1*1 m2, capacitance in vacuum 2 uF, which contains a dielectric material with dielectric constant K=5. The dielectric slides frictionlessly and is attached via a massless string and a massless pulley to a block of mass 2.5...
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    Question on directions of currents and magnetic fields

    5 pictures, 5 problems. Fourth one is the fourth picture. My book says I'm supposed to point my thumb in the direction of the current and look at how the fingers curl for magnetic field instead. Using what you just told me, I can get the solution to the fifth problem, but it doesn't help me...
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    Question on directions of currents and magnetic fields

    I did. Every single source I've read tells me I need two of the three vectors to find the third. The first one only gives me current, the second one doesn't give me anything, I just realized I can actually figure out the third one, the fourth one only gives me current, and the fifth one only...
  4. 1

    Question on directions of currents and magnetic fields

    How do I find the direction of these things? The right hand rule only works when I have the current and it's asking for clockwise/counter-clockwise, and the left hand rule only works when I have two of the three: Current, Magnetic Field, and Force. Example...
  5. 1

    Calculating emf in a Loop with Changing Magnetic Field

    Alright, it works now. Thanks for the help.
  6. 1

    Calculating emf in a Loop with Changing Magnetic Field

    Ok, and the integration of 4xydy from 0 to 0.02, and then multiplying that result by x is 0.000016. emf = d/dt * t^2 * 0.000016. Deriving gets 0.000032 * t Plug 1.5 into t to get 0.000048 V. Was the answer supposed to be positive?
  7. 1

    Calculating emf in a Loop with Changing Magnetic Field

    1. In the figure the square loop of wire has sides of length 2 cm. A magnetic field points out of the page; its magnitude is given by B = 4.0 t^2y where B is in teslas, t is in seconds and y is in meters. Determine the emf around the square at t = 1.50 s...
  8. 1

    How Do You Calculate Current Density in a Wire?

    Yeah, sorry, copy and pasted the question weirdly. Anyways, thanks for the correction. I got it figured out now.
  9. 1

    How Do You Calculate Current Density in a Wire?

    Homework Statement A long straight wire with circular cross-section and a diameter of 5.10 mm is made of a metal with resistivity = 5.00×10-8 m. The wire carries a current of 28.5 A. Calculate the current density in the wire. Homework Equations J = i / A The Attempt at a Solution...
  10. 1

    Electric Potential between two points

    So I just add the two electric potentials together instead of subtracting them? Could you explain why they add together instead of canceling? If I released the particle at the center, there wouldn't be any net force exerted on it, and it would remain stationary.
  11. 1

    Electric Potential between two points

    If the charge was on the opposite side of the point, the electric field lines would be pointing in the opposite direction, so wouldn't the opposite E-field lines become negative for potential and cancel out the other charge?
  12. 1

    Undergrad Electric Potential Concept Question

    Shouldn't it have the exact same value as the potential at infinity?
  13. 1

    Electric Potential between two points

    Homework Statement Two equal point charges Q = 5.18 C are separated by a distance d = 2.00 m. (See figure.) http://homework.phyast.pitt.edu/res/msu/nagytibo/Electromagnetism/Electrostatics/graphics/010a.gif Point A is halfway between the charges and point B is located 1.00 m to the...
  14. 1

    Undergrad Electric Potential Concept Question

    Alright... That's somewhat counter-intuitive for me. So does that mean that if I move a charge from infinity to the middle of the two opposite charges, no net work would be done?
  15. 1

    Undergrad Electric Potential Concept Question

    Why is the electric potential in the middle of two oppositely charged points 0? Does this also mean that there's no potential energy at this point?