# Help with a Simple Harmonic Motion problem!

1. Nov 18, 2007

### ceeforcynthia

1. A 25.0g bullet strikes a .600kg block attached to a fixed horizontal spring whose spring constant is 6.70x10^3 and sets it into vibration with an amplitude of 21.5cm. What is the speed of the bullet before impact if the two objects move together after impact?

2. V=A$$\sqrt{k/m}$$

3. I used the equation above, adding the masses together (.625kg). I got the velocity to be 22.26m/s... but now i can't figure out how to get the speed of the bullet.

The answer in the book says that the speed of the bullet is 557m/s.

Last edited: Nov 18, 2007
2. Nov 18, 2007

### nrqed

Use conservation of momentum. momentum of the bullet before the impact = momentum of the block plus bullet moving together at 22.26 m/s