In a hydroelectric dam, the gravitational energy of the water is converted into electrical energy as the water falls. Consider just one cubic meter (1000 kg) of water that falls a distance of 500 ft.
Assuming that the energy conversion is 100% efficient, how much electrical energy can be obtained as it falls?
Please express your answer both in joules and in kilowatt-hours.​

At a certain instant after jumping from the airplane a, a skydiver b is in the position shown and has reached a terminal (constant) speed vb = 52 m/s. the airplane has the same constant speed va = 52 m/s, and after a period of level flight is just beginning to follow the circular path shown of radius ρa = 2330 m. (a) determine the velocity and acceleration of the airplane relative to the skydiver. (b) determine the time rate of change of the speed vr of the airplane and the radius of curvature ρr of its path, both as observed by the nonrotating skydiver.