Question

your dogs wagging tail knocks over the cup of pencils sitting on your desk. what kind of force is his tail? an unbalanced force an inert force gravitational force friction

Explanation:

An unbalanced force causes a change in motion. The dog's tail wagging changes the motion of the cup of pencils from rest to moving, so it is an unbalanced force. Inert force is not a standard force term in basic physics. Gravitational force acts vertically downward due to Earth's pull and is not relevant here as the tail - to - cup interaction is horizontal. Friction is a force that resists relative motion between surfaces in contact and is not the force that knocked over the cup.

Answer:

an unbalanced force