Spinning wind turbine blades have kinetic energy. wind turbines transform this energy into electric energy and heat energy in a closed sytem. which of the following statements about this energy transformation is true? a. all of the heat energy is transformed into electric energy. b. half of the kinetic energy is transformed into electric energy and heat energy. c. all of the kinetic energy is transformed into electric energy and heat energy. d. half of the heat energy is transformed into electric energy.

1point) a skydiver weighing 130 lb (including equipment) falls vertically downward from an altitude of 14,000 ft and opens the parachute after 20 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.85|v|0.85|v| when the parachute is closed and is of magnitude 17|v|17|v| when the parachute is open, where the velocity vv is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. find the speed of the skydiver when the parachute opens. speed is 150.6121788 ft/s find the skydiver's height when the parachute opens. height is 2338.98591 ft find the limiting velocity vlvl after the parachute opens. (think about whether this should be positive or negative.) vl=vl= 7.647 ft/s

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects

Which of the following is the largest disadvantage of about half of the electricity in the united states comes from burning