INCORRECT: The normal force is always equal to the force of gravity.

CORRECT: Normal force is not always equal to force of gravity. Normal force is equal to the force of gravity if the object lies on a horizontal surface, the surface is not moving and the component of any external force in the direction of the normal is zero.

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INCORRECT: The coefficient of friction is equals to the friction force divided by force of gravity.

INCORRECT: The coefficient of friction is equal to the friction force divided by the normal force.

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INCORRECT: If the acceleration is constant, then the velocity is also constant.

CORRECT: If the acceleration is constant, the velocity is not constant. When the acceleration is zero, then the velocity is constant.