Thermodynamics: Internal Energy of a Gas

[Azndoode1]

Homework Statement

Helium (He), a monatomic gas, fills a 0.010-m^3 container. The pressure of the gas is 6.2 multiplied by 10^5 Pa. How long would a 0.38-hp engine have to run (1 hp = 746 W) to produce an amount of energy equal to the internal energy of this gas?

Homework Equations

Equations: DU = Q + W , Possibly PV = nRT?, Possibly DU = 3/2 n R T ?

The Attempt at a Solution

No idea how to go about doing this.

 

[Rick88]

Use PV = nRT and U = 3/2nRTtherefore U=3/2(PV).R.

 

[Azndoode1]

So using that, I get U = 9300J,
P= 290.32 W,
So how do I find the time?
Thanks.

 

[Rick88]

Do you know how power and energy are related to each other?

Or, more simply, what is power?

 

[Azndoode1]

Power = work / time
I substituted in, got 23 seconds, and that is not the right answer...
am I doing something wrong?

 

[Rick88]

My power is 283.48W,
which gives t=32.8 s.

 

[Azndoode1]

I redid it and I got 32.08. I think I missed a decimal?
Thanks for the help... i'll try that.

EDIT: Yup it worked! Thanks very much :)