If you want to double the kinetic energy of a gas molecule, by what factor must you increase its momentum?A) 16B) 2^(1/2)
C) 2D) 2*2^(1/2)E) 4

Respuesta :

Answer: [tex]\sqrt{2}[/tex]

The linear momentum [tex]p[/tex] is given by the following equation:

[tex]p=m.v[/tex]   (1)

Where [tex]m[/tex] is the mass and [tex]v[/tex] the velocity.

On the other hand, the kinetic energy [tex]K[/tex] is given by:

[tex]K=\frac{p^{2}}{2m}[/tex]   (2)

Which is the same as:

[tex]K=\frac{1}{2}m.v^{2}[/tex]

Now, if we double the kinetic energy, equation (2) changes to:

[tex]2K=2\frac{p^{2}}{2m}[/tex]  

[tex]2K=\frac{p^{2}}{m}[/tex]   (3)

So, if we want to obtain the kinetic energy as shown in (3), the only option that works is increasing momentum by a factor of [tex]\sqrt{2}[/tex] or [tex]2^{1/2}[/tex]:

Applying this in (2):

[tex]K=\frac{(\sqrt{2}p)^{2}}{2m}[/tex]

[tex]K=\frac{(2p)^{2}}{2m}[/tex]

[tex]K=\frac{p^{2}}{m}[/tex]>>>As we can see, this equation is the same as equation (3)

Therefore, the correct answer is B