Question

Two particles each of rest mass m collide head-on and stick together. Before collision, the
speed of each mass was 0.6 times the speed of light in free space. The mass of the final
entity is

Answer 1

$E_intial=E_final$

$Final velocity=0$

$\frac {MC^2}{\sqrt1-(0.6)^2}+\frac {MC^2}{\sqrt1-(0.6)^2}= \frac {MC^2}{\sqrt1-(0)}$

$\frac{2MC^2}{0.8}$

$M=\frac{5m}{2}$