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.

Archer puts muscular force to stretch the string. This will change the shape of the arrow. When the string is released arrow regains its original position which give it the initial force to set the motion. Because of gravitational from it come down towards after some time.