Q. When its 75kW engine is generating full power, a small single engine airplane with a mass of 700 kg gains altitude at a rate of 2.5 m/s. what fraction of the engine power is being used to make the air plane climb?
Q. A small city requires about 20MW of power. Suppose that instead of using high-voltage lines to supply the power, the power is delivered at 120V. Assume a two-wire line of 0.40cm -diameter copper wire, estimate the cost of the energy lost to heat per hour per meter. Assume the cost of electricity is about 10 cents per kWh.