*43.  An electron collides elastically with a stationary hydrogen atom. The mass of the hydrogen atom is 1837 times that of the electron. Assume that all motion, before and after the collision, occurs along the same straight line. What is the ratio of the kinetic energy of the hydrogen atom after the collision to that of the electron before the collision?

 

We have a collision so momentum is conserved

 

 

 

Because the collision is elastic, kinetic energy is conserved

 

 

From the conservation of momentum

 

From conservation of kinetic energy

 

Some comparing the two equations for

 

 

 

 

 

 

 

 

 

 

 

 

We are asked for the ratio of the hydrogen kinetic energy to the initial electron kinetic energy

 

 

 

 

 

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This page last updated on January 11, 2020