Changes

'''Normal force''' is the force exerted by a surface back up against the force of gravity. In the case of a mass present on a stationary surface perpendicular to the direction of gravity, normal force is equal to the force of gravity. Without the existence of normal force, a solid block would fall through a table.

'''Normal force''' is the force exerted by a surface back up against the force of gravity. In the case of a mass present on a stationary surface perpendicular to the direction of gravity, normal force is equal to the force of gravity. Without the existence of normal force, a solid block would fall through a table.