We investigate the effects of dry, sliding friction between a felt-covered wood block and a wooden table. By measuring the applied force and the acceleration of the block, we experimentally determine the force of kinetic friction and find that it is constant when the applied force is larger than a terminal frictional force Fttmg. However, we also find that the block continues to move without decelerating when the applied force is less than Ft. This strange behavior contradicts the common notion that the force of kinetic friction is constant and depends only on the normal force.

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