Question

A uranium nucleus (mass 238 units) at rest decays into two particles, a helium nucleus (mass 4.0 units) and a thorium nucleus (mass 234 units). If the speed of the helium nucleus is 6.0  105 m/s, what is the speed of the thorium nucleus?

Answer 1

Answer:

$0.103\times 10^5 m/s$

Explanation:

We are given that

Mass of uranium,$M=238 units$

Initial velocity,u=0

Mass of helium nucleus,$m_1=4 units$

Mass of thorium,$m_2=234 units$

Speed of helium nucleus,$v_1=6\times 10^5 m/s$

We have to find the speed of the thorium nucleus.

According to law  of conservation of momentum

Initial momentum=Final momentum

$0=m_1v_1+m_2v_2$

$m_2v_2=-m_1v_1$

$v_2=\frac{-m_1v_1}{m_2}$

$v_2=\frac{-4\times 6\times 10^5}{234}=0.103\times 10^5 m/s$