Calculus Help: When gas expands in a cylinder with radius r, the pressure P at any given time is a

When gas expands in a cylinder with radius r, the pressure P at any given time is a function of the volume V: P = P(V). The force exerted by the gas on the piston (see the figure) is the product of the pressure and the area: F = πr2p.
A cylinder on its side is given. A piston enters the cylinder from the left side and ends at the piston head a distance of x from the right side of the cylinder.
The volume of the cylinder to the right of the piston head is V.
The work done by the gas when the volume expands from volume V1 to volume V2 is as follows.
W =
P dv JV1
In a steam engine the pressure and volume of steam satisfy the equation PV1.4 = k, where k is a constant. (This is true for adiabatic expansion, that is, expansion in which there is no heat transfer between the cylinder and its surroundings.) Calculate the work done by the engine during a cycle when the steam starts at a pressure of 120 lb/in2 and a volume of 100 in3 and expands to a volume of 1000 in3. (Round your answer to two decimal places.)
W =
ft-lb