A redheaded woodpecker hits the bark of a tree extremely hard---the speed of its head reaches approximately

Question:

A redheaded woodpecker hits the bark of a tree extremely hard---the speed of its head reaches approximately v = 3.5 m/s before impact. If the mass of the bird's head is 0.060 kg, and the average force acting on the head during impact is F = 6. 0 N, find

(a) The acceleration of the head (assuming it is constant);

(b) The depth of penetration into the bark;