Recent content by jonpoux

  1. J

    Can an Infinite Hose Really Stop Water Flow?

    Indeed the answer in no: We can use the Navier-Stokes equation to demonstrate that the flow rate (Volume of fluid flowing through the hose per unit time) is proportional to the pressure gradient: the output of the hose is atmosferic pressure P0 and the input is P1>P0. So, the only way not to...
  2. J

    How Can You Measure the Speed of Light with Chocolate?

    I think that the distance between two spots won't be the wavelength: you have standing waves in the microwave, so that the distance between two nodes would be fractions of the wavelength depending on the mode...
  3. J

    Why does a ball go further if toe poked

    Hi everybody, I agree with robertm, I think that biomechanical reasons are the most important in this problem. Shooting with the toe is a "1D" movement as all your articulations will rotate around the same axis. Shooting with the side of the foot requires a lot of muscles to be "twisted"...
  4. J

    How to solve a Sum of Forces Problem with Two Springs and Varied Masses?

    Hi, Exactly, all of these questions can be solved from the Newton's equation F=ma. a) In this case, the equilibrium position is asked, so a=0 and sum of forces=0. In the sum of forces, you have the gravitation force mg and the reaction of the spring k(l-l0). In those kind of problems always be...
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