Which statement is true for the hang time of a projectile? a) it can be calculated solely by knowing the horizontal component of the velocity. b) it can be calculated solely by knowing the vertical component of the velocity of projection. c) it can be calculated solely by knowing the resultant velocity of projection. d) it can be calculated solely by knowing the angle of projection.

Atwo-stage air compressor operates at steady state, compression 10m^3/min of air from 100 kpa and 300k to 1200 kpa. an intercooler between the two stages cools the air to 300k at a constant pressure of 350 kpa. the compression processes are isentropic. a) calculate the power required to run the compressor, in kw b) compare the result to the power required for isentropic compression from the same inlet state to the same final pressure.