A horizontal piston-cylinder device contains air at 90 kPa while the outside pressure is 100 kPa. This is made possible by pulling the piston with a hanging weight through a string and pulley arrangement (see accompanying figure). If the piston has a diameter of 20 cm,
(a) Determine the mass of the hanging weight in kg.
(b) The gas is now heated using an electrical heater and the piston moves out by a distance of 20 cm. Determine the boundary work (include sign) in kJ.
(c) What fraction of the boundary work performed by the gas goes into the hanging weight?
(d) How do you account for the loss of stored energy (in the form of PE) by the hanging weight?