Driving Question:
How do the cords that are attached to the wheel make it come back up?
The reason that the wheel comes back up when it goes down is because as it is falling, the gravitational potential energy will change to kinetic energy and this is because of the wheel's descent and rotation. Once it has unwounded at the bottom it will jerk back up to the top and will change its linear momentum. It will continue to do this and it will slowly decrease in speed and start wiggling from side to side slightly. If you roll upwards the threads turning the wheel and then release it all the potential energy of the wheel converts to Kinetic energy of movement Kinetic energy of rotation. If you measure falling times for different positions you can get the momentum of inertia of the wheel easily using the principle of conservation of energy.
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