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Galilean Relativity

  • D1-44: ACCELEROMETERS AND FRAMES OF REFERENCE

    D1-44
    Demonstrate the direction of the acceleration in both rotational and translational coordinate systems
    In each experiment the ping-pong balls act as accelerometers. When the jars are rotated, the ball suspended from the bottom of the water-filled jar moves toward the direction of the acceleration, while the ball suspended from the top of the air-filled jar moves in the direction opposite the acceleration. The ping-pong ball in the water-filled tube indicates the direction of the acceleration when the tube is accelerated linearly or rotated.

  • F2-22: BUOYANCY PARADOX - ACCELERATED FRAME

    F2-22
    Illustrate dramatically the concept of buoyancy.
    A float is at rest in a water vessel suspended by a spring from a fixed point. The vessel is lifted up and released from rest, so that it oscillates vertically on the spring. In the picture above a band around the floater lies between the two bands around the larger vessel when the system is at rest.

    Q: How will the float move inside the water vessel as the vessel executes simple harmonic motion?

    A: Surprisingly, the float will remain at rest in the water vessel as it oscillates. It will even remain at rest when the vessel is stopped suddenly with your hand! See video 2 below. As the vessel oscillates, the weight density of both the floater and the water bath vary together, as the acceleration of the vessel varies, so the ratio of their densities remains the same, and they will continue to float with the same geometrical relationship!!