Atwood machine
Endless generations of students have solved the problem of the massless, non-stretching string passing over the pulleys with masses M and m on the ends.
The same principle is used for funicular railways with two connected railway cars on inclined tracks, and for the elevators on the Eiffel Tower which counterbalance each other.
Practical implementations[ edit ] Atwood's original illustrations show the main pulley's axle resting on the rims of another four wheels, to minimize friction forces from the bearings. Variations of the Basic Atwood's machine design were made well into the twentieth century.
Atwood machine with friction pulley
The picture at the right shows West Point cadets using an Atwood's machine about Atwood's Machine The Rev. It's column is topped with an pineapple; the Pixii machine at Marietta is topped with an acorn. This machine is listed at francs in the Deleuil catalogue. The same principle is used for funicular railways with two connected railway cars on inclined tracks, and for the elevators on the Eiffel Tower which counterbalance each other. The only one still in operation is the example at Marietta College, made by Pixii of Paris in the eighteen thirties. Many historical implementations of the machine follow this design. Ski lifts are another example, where the gondolas move on a closed continuous pulley system up and down the mountain.This machine is listed at francs in the Deleuil catalogue. In his book Atwood described a series of twelve demonstration experiments to be done with his apparatus.
At the top right is the top of an Atwood's machine in the collection of historical scientific instruments at the Smithsonian Institution. Many historical implementations of the machine follow this design. It's column is topped with an pineapple; the Pixii machine at Marietta is topped with an acorn.
At the top left is the top of an Atwood's machine made by Queen of Philadelphia, and, when I took the picture in Septemberat Wittenberg University, the apparatus was almost certainly upside down!