# Homework Help: Find the recoil velocity of the nucleus.

1. May 16, 2008

### looi76

1. The problem statement, all variables and given/known data
An alpha particle is emitted from a stationary nucleus at $$1.8 \times 10^7 ms^{-1}$$.The mass of the particle is $$4u$$ and that of the nucleus is $$212u$$. (u is a unit of mass equal to $$1.66 \times 10^{-27}kg$$.)
(a) Find the recoil velocity of the nucleus.
(b) Explain how you know the direction of movement.

2. Relevant equations
Momentum before collision = Momentum after collision

3. The attempt at a solution
What does recoil velocity mean?

2. May 16, 2008

### alphysicist

Hi looi76,

The recoil velocity of this nucleus is the velocity of the nucleus after the alpha particle is emitted. What do you get?