Recent content by Jim Kadel

  1. J

    How Long and How Fast Do Divers Fall from Different Heights?

    As a former teacher of H.S. physics, I find that the rules of this forum actually prevent what I consider to be "help". So having unintentionally violated, and not being in agreement with the one rule that states "no solutions allowed", I will no longer participate.
  2. J

    Finding Spring Constant from Mass and Extension

    Altho it doesn't specify it in the description, the assumption is that said spring is hanging vertically, so the weight of the block = mg is the force that extends the spring a distance = 10 cm. Hooke's Law: Spring's force (mg) is directly proportional to the extension distance: F = kx...
  3. J

    Calculate the work done when a conductor moves through a mag

    The work done will be the energy dissipated by the closed circuit loop. This loop carries a current = I = 36/4.3 = 8.3721 a. The electrical power in this circuit = VI. Power = VI = 36(8.3721) = 301.3953 Work = Energy used = Power • time Where the time for loop to move a distance = 0.932 m at...
  4. J

    How Much Work is Done by Gravity?

    Just observing U R attempts at sol'n: The only one that makes sense to me, according to the question asked is the 2nd attempt using PEg = mgh. The force of gravity being "mg" the weight of Y.I. and h being her vertical displacement. Now then this computed value has UNITS of J and can only be...
  5. J

    Initial velocity and time of motion through water

    I would say, no, the time formulas quoted are for object's Free-Falling from rest. The problem states that the ball has an initial {unknown} velocity when dropped in air from a height = 1 m. Then it will also have the necessary initial velocity when it enters the water to drive it down a...
  6. J

    Momentum vs Inertia: Is Momentum a Measure of Resistance?

    Inertia is a conceptual quantity that is rather unique in physics. It is *not* a physical quantity since it has no units. It's very much related to the physical quantity of mass but is not exactly ≡ same thing .
  7. J

    Archimedes' Buoyancy: Which Ball Will Experience a Greater Buoyant Force?

    Back to the original question: not poorly worded, IMHO, but... ..it would seem simply a case of the answer key being incorrect: A instead of C for "the floating situation". [It happens, altho students claim it much more frequently :>]
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