As punishment, Zeus banished him to Hades, where he was doomed for eternity to roll a rock up hill, only to have it roll back on him. If Sisyphus stands in front of a 400 lbs spherical rock on a 20 degres incline, then what force applied in the direction of the incline would keep the rock from rolling down the incline.

 Jan 24, 2019
edited by Guest  Jan 24, 2019

\(\text{If you draw the force diagram you see that the gravitational force on the rock}\\ \text{can be broken up into a component normal to the inclined ground and a component }\\ \text{along the direction of potential motion}. \text{The magnitude of the component along the direction of potential motion is}\\ |f_m| = 400 \sin(20^\circ) \approx 136.8~ lbs\\ \text{This is the force that must be applied to the rock in the direction of the incline}\)

 Jan 24, 2019

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