Which statement is true about the ideal mechanical advantage of a third-class lever?
A It is always greater than 1.
B It is always equal to 1.
C It is always less than 1.
D It can be less than, greater than or equal to 1.

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)