What Is the Net Force on Each Side of a Heated Sealed Box?

AI Thread Summary
The discussion revolves around calculating the net force on each side of a heated sealed box containing air. Initially, the box is at 1 atm and 300K, and when heated to 400K, the pressure increases to approximately 4/3 atm. The net outward force on each side is calculated by considering the pressure difference between the internal air pressure and the external atmospheric pressure. The final consensus suggests that while the outward force can be calculated, the net force on each side of the box is effectively zero when considering equal forces acting in opposite directions. The key takeaway is that the net force is determined by the pressure differential across the box's walls.
jin
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thermal expansion?

I need help asap! the question goes like this...

A cubic metal ox with sides of length 20cm contains air at pressure of 1 atm and a temperature of 300K. the box is sealed so that the volume is constant and heated to 400K. what is the net force on each side of the box? :confused:
 
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PV = nRT --> P/T = nR/V = const.
P0= 1 atm T0=300k
P1= P0*T1/T0 = 4/3 atm = 135100 Pa
F= (P1 - Patm)* S = (135100 Pa - 101325 Pa)* (0.2m^2 * 6) = 8106 N

Bye Final
 
jin said:
what is the net force on each side of the box?
Well, I presume the net force on each side is zero! :smile:

But I suppose they want you to find the outward force on each side of the box due to the pressure of the enclosed air.

If you can assume that this box is itself in air at atmospheric pressure, then you can find the net force due to air pressure by subtracting the outside air pressure, like Final did.
 

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