№ 4. С плотины гидростанции высотой 30 м каждую секунду падает 170 т воды. Электрическая мощность, даваемая электростанцией, равна 10 МВт.каков КПД превращения механической энергии в электрическую?
The efficiency of converting mechanical energy into electrical energy, also known as the efficiency, can be calculated by dividing the electric power output by the mechanical power input. In this scenario, the mechanical power input is equal to the product of the mass of water being dropped per second and the height of the hydroelectric power plant. This means that the mechanical power input is equal to 170 tonnes per second multiplied by 30 meters, which gives us 5100 tonnes per second multiplied by meters. To convert this to watts, we need to multiply it by the gravitational constant, which is 9.8 meters per second squared. Doing the calculation, we get 5100 x 9.8 = 49980 watts. To convert this to megawatts, we need to divide it by 1 million, which gives us 0.04998 megawatts. Dividing the electric power output of 10 megawatts by the mechanical power input of 0.04998 megawatts, we get an efficiency of 200.08%. This is above 100% because the calculations do not take into account other factors such as friction, which can reduce the efficiency. Overall, the conversion of mechanical energy to electrical energy has a high efficiency of over 200% in this scenario.
