English: Inclined plane educational instrument used in science classes in the early 18th century. A weight on wheels (visible hanging from apex at left) ran in the groove along the top. It was pulled up the track by a string that ran over a pulley at the apex, and down to the suspended weight visible at left. By adjusting the weights until the device didn't move (was in static equilibrium), the mechanical advantage could be measured by dividing the two weights.
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