Problem #1
A) At a certain location, wind is blowing steadily at 10 m/s. Determine the mechanical energy of
air per unit mass and the power generation potential of a wind turbine with 60-m-diameter blades
at that location. Take the air density to be 1.25 kg/m$^3$.
B) Consider a river flowing toward a lake at an average velocity of 3 m/s at a rate of 500 m$^3$/s at
a location 90 m above the lake surface. Determine the total mechanical energy of the river water
per unit mass and the power generation potential of the entire river at that location.
River 3 m/s
90 m
C) Water is being heated in a closed pan on top of a range while being stirred by a paddle wheel.
During the process, 30 kJ of heat is transferred to the water, and 5 kJ of heat is lost to the
surrounding air. The paddle-wheel work amounts to 500 N \cdot m. Determine the final energy of the
system if its initial energy is 10 kJ.
5 kJ
500 N\cdot m
30 kJ
D) What are the mechanisms of heat transfer?