(a) To stretch the bow, the archer applies a force that causes a change in its shape.
(b) The force applied by the archer to stretch the bow is an example of muscular force.
(c) The type of force responsible for a change in the state of motion of the arrow is an example of a contact force.
(d) While the arrow moves towards its target, the forces acting on it are due to gravity and that due to friction of air.
When the archer stretches the bow, then he applies muscular force on the bow using his hands and thus stretches the bow by changing its shape.
Now there is a change in state of the arrow which was in contact with the bow. As a result it proves that some force is exerted on the arrow that had brought change in its state of rest, and this force is called as contact force.
When the arrow moves forward, as it moves above the ground level, hence the earth exerts a downward force on it due to gravity. And as it moves through the air, the air opposes its motion by resisting its motion in the forward direction because of the friction of air.