Ahelicopter winches up an injured person from a boat. the person plus the equipment that must be pulled up with the person has a mass of 109 kg. the efficiency of the motor (the actual work done divided by the electrical energy consumed expressed as a percentage) is 69%. if the height of the lift is 83 m and it is carried out at a uniform rate over 55 s, what is the power expended by the helicopter's winch motor? (give your answer in watts)

In what direction does the medium move relative to the direction of the wave? explain.

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

An object is 10 cm from the mirror, its height is 1 cm and the focal length is 5 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1 -1 +10 -10