Question

As the gas in a cylindrical piston of radius r expands, the piston moves and work is done. if p represents the pressure of the gas (In pounds per square foot) against the piston head and V represents the volume of the gas (in cubic feet), the work increment involved in moving the piston is....Delta W = F(delta x) = p((pi)r^2)delta x = p(delta V)....Draw appropriate pictures and reason through the above equation....Can some one please help! Medal when finished...