2. A pump with a power output of 600 W raises water from a lake through a height of 3.0 m and delivers it with a velocity of 6.0 ms-1. What mass of water is removed from the lake in one minute? Answer is 750kg but I don't know how to get the answer.

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?

Can anybody me with this? ? (picture included.)

How does an observation about an object differ from an inference about that object