Answer:12.28m/s
Explanation:
momentum of baseball =mass of baseball x velocity of baseball
Momentum of baseball =0.31x21
Momentum of baseball =6.51kgm/s
For a softball to have same momentum with the baseball we can say :momentum of baseball =mass of softball x velocity of softball
6.51=0.53 x velocity of softball
Velocity of softball =6.51/0.53
Velocity of softball =12.28m/s