For Exercises 16–20, refer to the following. Energy can be thought of as power applied over time. Power can be measured in kilowatts and energy in kilowatt-hours (kWh), where 1 kilowatt-hour is 1000 watts of power exerted for 1 hour. For example, a 40-watt bulb burning for 24 hours consumes 960 watt-hours ≈ 1 kWh. Other forms of energy, such as food or gasoline, can be converted to an equivalent in kWh.