# Nuclear fission

1. Jan 3, 2015

### Tomos

1. The problem statement, all variables and given/known data
Question 5 (c) (ii) from the paper physics 2 higher tier January 2014 by wjec. There is no mark scheme at the moment of the paper and I do not understand the question. The paper is at the bottom of "papers" at http://www.wjec.co.uk/qualification...tml?pastpaper=true&subject=Physics&level=gcse and the question is " if a barium nucleus is released with the same kinetic energy as a neutron, explain why the size of its velocity would only be one twelfth (1/12) of the velocity of a neutron". Please help!

2. Relevant equations
N/A

3. The attempt at a solution
Barium has a greater mass than a neutron???

Last edited by a moderator: Jan 3, 2015
2. Jan 3, 2015

### PWiz

KE in this case is given by $\frac{1}{2} mv^2$ . You're close when you think about the difference in masses. What is their ratio? How does $m$ relate to $v$? Think about it.

3. Jan 3, 2015

### Tomos

Okay thanks!

4. Feb 27, 2015

### Zacpearson

With a greater mass and an equivalent kinetic energy, the velocity of the barium nucleus will be much small considering the mass is so much greater than that of the neutron. Ke=(1/2) mv^2 therefore if you set up a proportion you could calculate the velocity of the neutron compared to the barium.