Question

A piston/cylinder,  contains air at 1380 K, 15 MPa, with V₁ = 10 cm³, Acyl = 5 cm². The piston is released, and just before the piston exits the end of the cylinder the pressure inside is 200 kPa. If the cylinder is insulated, what is its length? How much work is done by the air inside? 

Answer 1

C.V. Air, Cylinder is insulated so adiabatic, Q = 0. Continuity

Eq.: m₂ = m₁ = m,

We could also have done V₂ = V₁ (T₂P₁/T₁P₂) from ideal gas law and thus did not need the vr function for this problem