Ex 1) A Major League baseball pitcher throws a baseball straight up into the air and the ball travels for 4 seconds reaching a height of 52 m before returning to the pitchers hand exactly at the height that he released
it. With what velocity does the baseball strike the pitchers hand on the way back down?

The consumption of fossil fuels could be

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?