# Thermodynamics- total kinetic energy and rms velocity

 P: 3 Find total kinetic energy and root mean square velocity of the molecules of 10 liters of helium gas at an equilibrium pressure of 105 N m−2. Density of helium is 0.1786 gram/liter. I am having trouble with the question, I know: K=(Nm)/2 PV=(Nm )/3 but I am not sure how to apply this. Any help would be appreciated.
HW Helper
P: 6,679
 Quote by xxx23 Find total kinetic energy and root mean square velocity of the molecules of 10 liters of helium gas at an equilibrium pressure of 105 N m−2. Density of helium is 0.1786 gram/liter.
Can you find the temperature? What is the relationship between temperature and kinetic energy?

AM
 P: 3 I have partial solutions from my tutorial but they are not making too much sense... From the above equations, it goes: K= 1/2 Nm ^2 so if divide each side by V K= 1/2 ρ V ^2 from here the solution goes: PV=1/3 Nm ^2 K=3/2 PV I can see that 2K=3PV but i do not understand where the following equations come from: K=1/3 ρ V ^2 because this is what i need to rearrange to find Vrms.
 Sci Advisor HW Helper P: 6,679 Thermodynamics- total kinetic energy and rms velocity You did not answer my questions. AM
 P: 3 I know that as the temp increases so does the kinetic energy. 1/2 m ^2 = 3/2 KT