Question

D. An ideal gas is contained in a cylinder that is fixed in Ideal gas place. The cylinder is closed by a piston, as shown in the diagram at right. There is no friction between the piston and the cylinder walls. 1. Describe the direction of the force that the piston exerts on the gas. Does your answer depend on whether the piston is moving? 2. How could the piston move so that the work it does on the gas is: . positive? • negative? Do your answers depend on your choice of coordinate system? 3. In each of the two cases in part 2, is there work done on the piston by the gas? If so, how is that work related to the work done on the gas by the piston? (Consider both sign and absolute value.) -> Check your answers with a tutorial instructor before you continue. Insulating jacket II. Work and internal energy A. Imagine that the cylinder from section I is thermally insulated from its surroundings by placing it in an insulating jacket. The piston is pressed inward to the position shown at right. We will refer to this compression as process 1. Ideal gas work done on the gas by the piston during process 1 positive, negative, or zero?

Answer 1

ideal gas Note that gas exerts force on piston towards right so piston exerts force gas towards. It does not depend on direction as far as force by piston on gas is concerned. gas by piston isü Dositive it pistons moves towards left. gas by biston is negative af piston move towards right. 2) work-done on work-done on 3) work done by piston on gas is positive then was k done by gas is negative and vice-ver s worn-aone by gay on piston, work done by piston on gas 18 rela led. work and internal energy force applied by poston As piston is moving to left ie in the direction of so work done on gas by po's too is positive.