An archer shoots an arrow in the air horizontally. However, after moving some distance, the arrow falls to the ground. Name the initial force that sets the arrow in motion. Explain why the arrow ultimately falls down?

The archer shoots an arrow by applying muscular force to stretch the string of the bow. When the archer releases the string, the string tends to regain its original position and this provides the initial force to set the arrow in a horizontal motion. The arrow ultimately falls down due to the force of gravity that acts on the arrow.