A question about momentum

[wowolala]

1.) A particle with mass M initially at rest decays into two identical particles each of mass 0.48M, the speed of the identical particles after the decay is :



after decaying , the sum of two mass doesn't equal to initial mass...


can somebody help me how to solve this qusiton


2.)if a particle whose rest mass energy equals 100MeV has a total energy of 200Mev, its velocity is :


i think there is some kind of relation between 1 and 2.

please help me ?

thx

 

[alphysicist]

Hi wowolala,

1. Now that the particle has decayed and the two identical particles are moving away, in what form of energy has the "missing" rest mass energy been converted to?

2. How is the total energy related to the rest mass energy?