If we double the resistance in a circuit but keep the current constant, how will the power dissipated by that circuit change?

(II) Water is stored in an artificial lake created by a dam (Fig. 20–22). The water depth is 48 m at the dam, and a steady flow rate of 35 m³/s is maintained through hydroelectric turbines installed near the base of the dam. How much electrical power can be produced?

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Suppose it takes 75 kW of power for your car to travel at a constant speed on the highway. What is this in horsepower?

A “60-watt equivalent” LED lightbulb is rated at 7.5 W and 800 lumens. How much power goes into light? (The rest goes into heat.)

How much power must an elevator motor supply in order to lift a 1000 kg elevator at constant speed a height of 100m in 50 seconds?

A $20.0$-kg rock is sliding on a rough, horizontal surface at $8.00$ m/s and eventually stops due to friction. The coefficient of kinetic friction between the rock and the surface is $0.200$. What average power is produced by friction as the rock stops?