Recent content by wombat7373

  1. W

    How can this function be simplified?

    so x is imaginary?:confused:
  2. W

    Electrostatic potential energy for concentric spheres

    I suppose I'll buy it just because the electric field ends up being constant like with two plates. So to find the energy I just do U=(1/2)QV. I suppose I could calculate the potential difference by integrating the electric field over that 0.5 cm distance. Would that be the way to do it?
  3. W

    Particle sliding off turntable - find friction

    Force is related to acceleration by F=ma The centripetal force is the force that is required to produce the centripetal acceleration. F_c=ma_c = \frac{mv^2}{r} Make a diagram of all the forces on the particle and figure out what the friction has to be, keeping in mind that the net force must...
  4. W

    Find Derivative of f(x) = x - \sqrt{x}

    U can also use the addition rules of limits to calculate derivatives for x and sqrt x separately and then add them.
  5. W

    Find Derivative of f(x) = x - \sqrt{x}

    My comp. is being stupid so I can't write the whole thing =\ I had a test once where we had to do a lot of those derivatives without the shortcuts. U can solve it that way by multiplying both the numerator and the denominator by \sqrt{x+h}+\sqrt{x}\\ edit: yay my comp is working let's give...
  6. W

    Find Derivative of f(x) = x - \sqrt{x}

    Got it...working on the tex
  7. W

    Find Derivative of f(x) = x - \sqrt{x}

    Using the limit definition is so tedious :(
  8. W

    Find Derivative of f(x) = x - \sqrt{x}

    I just tried it and got a wrong answer. Your goal is the get everything in the numerator so that it has an h in it. That way u can cancel out the h on the bottom.
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    Particle sliding off turntable - find friction

    Why are you more eloquent than I am?
  10. W

    Particle sliding off turntable - find friction

    Well there are two ways to look at it: centripetal and centrifugal. I'll explain centripetal one since some people get mad about centrifugal forces. In order for the particle to be moving in a circle, it needs a centripetal force. Figure out what forces are acting on the particle and do a...
  11. W

    Electrostatic potential energy for concentric spheres

    Two concentric metal spheres have radii r_1 = 10 cm and r_2 = 10.5 cm. The inner sphere has a charge of Q = 5 nC spread uniformly on its surface, and the outer sphere has charge -Q on its surface. (a) calculate the total energy stored in the electric field inside the spheres Hint: You can treat...