Chapter 4 Question 5 Answer:

(4) Wi > Wg > Wa > Wp

Work input from the motor, Wi:

Power input = 3A (12V) = 36 J/s, Time = 50 s

Wi = 36 J/s (50s) = 1800 J

Work to raise the piston, Wp:

Wp = Force (distance) = 100kg (9.8m/s2) 0.1m = 98 J

Work to push against the atmosphere, Wa:

Wa = Force (distance) = 105 N/m2 (0.05 m2) 0.1m = 500 J

Work done by the gas, Wg:

Wg = Wp + Wa = 598 J

(The net work of the system = 598 J - 1800 J = -1202 J, thus in sum work is done on the system.)

Therefore Wi >Wg > Wa > Wp

It is possible to arrive at a different answer if you put a negative sign in front of the work done by the motor. This is a very minor error. Technically, I asked for the work input, so the sign was specified by the word "input", so you shouldn't put a negative in front of it.