67. i a 200 kg weather rocket is loaded with 100 kg of fuel and
fired straight up. it accelerates upward at 30.0 m/s2 for 30.0 s,
then runs out of fuel. ignore any air resistance effects.
a. what is the rocket's maximum altitude?
b. how long is the rocket in the air?
c. draw a velocity-versus-time graph for the rocket from liftoff
until it hits the ground.

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)