Final answer:
The pencil and notebook are not being pulled together by gravity because the forces acting on them are balanced and in equilibrium.
Step-by-step explanation:
The pencil and notebook resting on your desk are not being pulled together by the force of gravity between them because the forces acting on them are balanced and in equilibrium. When an object is at rest or moving at a constant velocity, the net force on the object is zero, according to Newton's first law of motion.
In this case, the weight of the pencil and notebook are balanced by the normal force exerted by the desk. The normal force is an upward force exerted by a surface to support the weight of an object resting on it. The magnitude of the normal force is equal to the weight of the object.
Since the weight of the pencil and notebook pull them downward, and the normal force exerted by the desk pushes them upward with equal magnitude, the forces cancel each other out and there is no net force to cause them to move together.