Is the table tilted? then gravity is the other force. Friction force only exists if there is a force trying to move an object.
so there is no static friction when a block is just sitting there and not moving with no applied force?
no, of course not. Don't get into the question if no one is in the forest to hear the tree fall, does it make a sound.
The equal and opposite force to the force of friction is the force exerted by the block on the table, also known as the reactive force or the normal force. When an object is at rest on a surface, such as a block on a table, the force of static friction acts in the opposite direction to any applied force that tries to move the block. In this case, the static friction force is exerted by the table on the block, preventing it from sliding. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. Hence, the block exerts an equal and opposite force on the table, known as the reactive or normal force.
