I don't understand why answer choice 8 is wrong... I thought that for an elastic collision, V1 (initial velocity of the hammer) would equal V2' (final velocity of the ball). Thank you in advance :).

018 10.0 points Consider the elastic headon collision between a sledge hammer with 8000 g mass and a golf ball with a 5 g mass. The initial velocity of the sledge hammer is 14 m / s , and the golf ball is initially at rest. Estimate the approximate nal speed 122 of the golf ball. 1. '0; m 28 m/s 2. v; m 4.45634 m/s 3. n; m 140 m/s 4. 05 m 56 m/s 5. 1:5 m 43.9823 m/s 6. U? ~ 112 m/s 7. 02 140 m/s 8. 02 ~ 14 m/s 9. U2 ~ 70 m/s 10. U2 ~7 m/s