[填空题]
A 23-g bullet traveling;-s cdpj-*kg x 2m1tzlcvhn36 ; c6 z6d(9yxnle8yw9ka 30m/s penetrates a 2.0-kg block of wood and emerges cleanly at 170m/s If the block is stationary on a he(w63;n am n yz89cc9tl6yld61vz kxfrictionless surface when hit, how fast does it move after the bullet emerges? m/s
