# Momentum help.

#### botab

I need help with this problem where we are suppose to determine the fraction of kinetic energy lost by a neutron m=1.01u when it collides head-on and elastically with a target particle at rest which is.

examples used..
Hydrogen = 1.01u
heavy hydrogen = 2.01u

How would you do this?
Do we use .5MaV^2 +.5MbV^2 = .5Ma'V^2 + .5Mb'V^2 + energy loss?

examples used..
Hydrogen = 1.01u
heavy hydrogen = 2.01u

Thanks again,

#### skand

hello,
such questions can be solved using Conservation Of Momentum,and Work Energy theorem(that you used)

1st derive a relation between velocities of masses(call $$v_1\ and\ v_2$$)

then use the equation you are using

thanks

Last edited:

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