Finding Dissociation energy , path of the particle involved

[imvaibhav]

Homework Statement

Beam of excited H₂ molecules travels in z direction, kinetic energy 1 eV.Then they decay & dissociate into 2 H-atoms.When one of the H atom has its final velocity perpendicular to z axis, its kinetic energy is always 0.8eV. Then what is the energy released in dissociative reaction?
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Homework Equations

The Attempt at a Solution

How does the path effect the energy?
I am totally clueless about the question (Actually its not my homework problem, i came across it somewhere.
Any useful hint or the theory would also help.)Hoping to get replies..

 

[Andrew Mason]

Homework Statement

Beam of excited H₂ molecules travels in z direction, kinetic energy 1 eV.Then they decay & dissociate into 2 H-atoms.When one of the H atom has its final velocity perpendicular to z axis, its kinetic energy is always 0.8eV. Then what is the energy released in dissociative reaction?
.

How does the path effect the energy?

You have to first apply conservation of momentum. Draw the vector of the momentum of the H₂ molecule. Then draw the momentum vector of the H atom that is moving perpendicular to the z axis. What does the difference between these two vectors represent? (Hint: what does the momentum of the other H atom and the momentum of H atom moving perpendicular to the z axis add up to?).

Once you have the momentum vectors worked out, work out the energy of the two H atoms and compare it to the energy of the H₂. Are they the same?

AM