The ratio between the force of sliding friction and the normal force of an object is called

-rolling friction
-the drag
-the coefficient of friction
-the starting friction

The ratio between the force of sliding friction and the normal force of an object is called the coefficient of friction.

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Answer;

The coefficient of friction

Explanation;Friction is a force that opposes motion. Normal force on the other hand is a force that presses two surfaces together and is directed perpendicular to the contact surface; on a level surface. The magnitude of normal force is equal to the force of the object's weight but in the opposite direction.The coefficient of friction shows the relationship between the force of friction between tow objects and the normal force between those objects.

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