Conservation of energy- setting it up

[Fellowroot]

Homework Statement

Homework Equations

The Attempt at a Solution

I do not understand how in the solution they come up with the first equation that I boxed in with green.

I know that the total energy before is equal to the total energy after but I don't understand the logic of how they formed that first equation. It looks like KE+KE=E to me. What happened to the PE potential energy? And how can the KE of the 2 He atoms be equal to the energy released with the atoms?

I would only think that it would be (PE)_Beryllium= 2(KE+PE)_Helium+92.0keV

Also, I am two days into the class and my physics teacher has NOT solved a single problem. Has this happened to anyone else?

EDIT: OK, I think I got it? 92.0keV of energy is released which goes into the two He particles and somehow they are traveling at Vmax so there is no PE? That's my guess.

 

[Fellowroot]

OK, I asked my teacher why the PE was not in the equation.

He said something about how the gravitational PE is so small that you can neglect it.

This is now the third day of class and he has NOT solved a single problem or done an example on the board.