A rider moves at constant height in a horizontal circle on the inner wall of a cylindrical Well of Death. Which force provides the centripetal force?
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A rider moves at constant height in a horizontal circle on the inner wall of a cylindrical Well of Death. Which force provides the centripetal force?

G1 Physics · Accepted Answer

The wall's normal reaction is horizontally directed toward the axis of the cylinder. Therefore it supplies the centripetal force: N_R = mv²/r. Static friction acts vertically upward to balance the rider's weight when the rider remains at constant height.