Aball attached to a string of 2m is raised to an angle of 38 degrees below the horizontal and then released. a) what is the expected velocity of the ball when it reaches the bottom of its swing, neglecting air resistance?
b) it was measured that the actual velocity was 3.0 m/s. what was the work done by air resistance if the mass of the ball is 0.5 kg?

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)