Air in a pistoncylinder device shown is in equilibrium at 20

Air in a piston-cylinder device shown is in equilibrium at 200 C. If the mass of the hanging weight is 10 kg...etc.

Please check the picture...

Thanks.

Solution

pressure of the air inside=F/A+ atmospheric pressure

    F=10x9.81=98.1N

A= pi r² here r is the radius of the piston

=3.14x 5² =78.5cm² =78.5x10^-4 m²

thus pressure= (98.1/78.5x10^-4 ) -100000 pa =87.5kpa

(b) There is no change in the pressur if the gas is replaced by hydrogen.