PURPOSE: To show the difference between pendula with small amplitude and large amplitude of oscillation, and to show rotational motion where the kinetic energy at the top is much less than the change of potential energy from the top to the bottom of the oscillation.
DESCRIPTION: The Oberbeck Cross is used with three of the weights removed and one at its maximum radius. The motion of the pendulum for various amplitudes, including complete rotation, can be simply observed or can be compared with computer simulations of the 360 degree pendulum. Because of the large change of potential energy, the velocity of the bob changes significantly when it is given just enough energy to undergo full circular oscillations.
SUGGESTIONS: Block up the wheels with 4x4 block to prevent unwanted motion of the entire apparatus.
REFERENCES: (PIRA 3A95.33)
EQUIPMENT: Oberbeck Cross, wooden block
SETUP TIME: None.
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