Ratio of the velocities of two atoms, based on kinetic energy

AI Thread Summary
The discussion centers on calculating the ratio of velocities between a helium atom and an oxygen atom, given that they possess the same kinetic energy. The oxygen atom is four times more massive than the helium atom. By applying the kinetic energy equation, the user rearranges the terms to isolate the velocity ratio. The final calculation shows that the ratio of the speeds is vHe/vO = 2, indicating that the helium atom moves twice as fast as the oxygen atom. This conclusion is reached through basic algebraic manipulation of the kinetic energy formula.
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Homework Statement



An oxygen atom is four times as massive as a helium atom. In an experiment, a helium atom and an oxygen atom have the same kinetic energy. What is the ratio vHe /vO of their speeds?



Homework Equations


K=.5mv2


The Attempt at a Solution



.5mHe(vHe)2=.5(4mHe)(vO)2

I'm not sure what to do with that though, how to solve for the ratio.
 
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Have you learned basic algebraic manipulation? You just have to rearrange the equation so as to get the ratio V(he)/V(o) on one side. eg. 5a = 3b, a/b = ?
 
Oh my, I was making that much harder than it needed to be.

What I got:
.5mHe(vHe)2=2mHe(vO)2
mHe cancels to give (vHe)2=4(vO)2
(vHe)2/(vO)2=4
vHe/vO=\sqrt{}4=2
 
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