Recent content by jimithing

  1. J

    How Much Internal Energy Increases in a Damped Oscillating System?

    I got F = \frac{q^2}{4\pi \epsilon_{0}(3d)^2} , F = -k(3d) So k = -\frac{q^2}{4\pi \epsilon_{0}27d^3} Do I now just sub into U = \frac{1}{2}k(3d)^2 ?
  2. J

    How Much Internal Energy Increases in a Damped Oscillating System?

    A light unstressed spring has length d. Two identical particles, each with charge q, are connected to the opposite ends of the spring. The particles are held stationary a distance d apart and then released at the same time. The system then oscillates on a horizontal frictionless table. The...
  3. J

    What Is the Optimal Selling Price for a Paint Mixture with 17.0% Pigment?

    i assumed that the 25% and 12% mixtures were sold at cost, so i used .25x + .75y = 18 and .12x + .88y = 10 solved for x and y, then substituted into .17x + .83y = z found z, multiplied by 1.1 hopefully that's what they're looking for
  4. J

    What Is the Optimal Selling Price for a Paint Mixture with 17.0% Pigment?

    A paint mixture containing 25.0% pigment and the balance water sells for $18.00/kg, and a mixture containing 12.0% pigment sells for $10.00/kg. If a paint retailer produces a blend containing 17.0% pigment, for how much ($/kg) should it be sold to yield a 10% profit? Am I wrong, or are they...
  5. J

    Quick question regarding gauss' law

    A long coaxial cable consists of an inner cylindrical conductor with radius a and an outer cylindrical shell of inner radius b and outer radius c. The cylindrical shell is mounted on insulating supports and has no net charge. The inner cylinder has a uniform positive charge per unit length...
  6. J

    Point charge in an electric field

    i figured it out earlier today F = ma qE = ma \frac{eE}{m}= a find a, use it to find the displacement (x) in the simple mechanics equation \frac{-v_{0}^2}{2a}= x then use x to find t : \sqrt{\frac{2x}{a}}= t now simply use: \Delta KE = \frac{1}{2}mv_{0}^2 -...
  7. J

    Electric Charges: Solving a Half Sphere Problem

    another hint - the electrical field outside a spherical shell of charge with radius r and charge q is directed radially and has magnitude E = \frac{q}{4\pi \epsilon_{0}r^2}
  8. J

    Electric Charges: Solving a Half Sphere Problem

    use a gaussian surface and take advantage of its symmetry, but make sure your point P is on the GS or else there will be error. \Phi = \oint E \cdot dA E will be constant, so it can be taken out of the integration, etc.
  9. J

    How Much Force Must a Diving Suit Window Withstand at 150m Depth?

    The viewing window in a diving suit has an area of 65 cm^2. If an attempt were made to maintain the pressure on the inside of the suit of 1 atm, what force would the window have to withstand if the diver descended to a depth of 150 m. Take the specific gravity of the water to be 1.05. So...
  10. J

    What is the correct direction for the explorer's displacement to return home?

    just use vector addition for the direction (head to tail addition)
  11. J

    Point charge in an electric field

    the thing is, is that we haven't studied potential...i was trying to work this problem using strictly kinematics...
  12. J

    What is the correct direction for the explorer's displacement to return home?

    try 120 degrees for the second batch of steps (60 degrees north of west)
  13. J

    Point charge in an electric field

    could you define u, s, V, W, and Q
  14. J

    Point charge in an electric field

    here can \vec {a} be represented by \frac{v^2 - v_o^2}{2(x - x_o)} , with v being the velocity given?
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