A bullet of mass 2.90 x 10-3 kg, moving at 1210 m/s impacts a tree stump and penetrates 8.00 cm into the wood before coming to rest. (Take the direction of the bullet to be in the positive direction.)
(a) Assuming that the acceleration of the bullet is constant, find the force (including direction) exerted by the wood on the bullet.
(b) If the same force acted on the bullet and it had the same impact speed but half the mass, how far would it penetrate into the wood?