[填空题]
A 12-kg hammer strikes a nail at a velocity of 8.5m/s and 4is.y: 8 6ffz rfjnuka-c-co cs0h-*ocomes to rest in dr.8errda5j ;i7x 8z39ayz rra time interval of 8.0 ms. (a) What is the impul5aar7 rr;3edr8dz 98yz.jxi rse given to the nail? kg*m/s
(b) What is the average force acting on the nail? N