Watt- second -or kilowatt means

Answer 1

You should think of "watt" as a rate or speed ... it's the speed of using energy, but instead of

speed, it's called "power".

1 watt means that 1 joule of energy is being used every second.

1 watt-second means the amount of energy used in one second, when it's used at the rate of 1 watt.

In the last paragraph, we just said that this is 1 joule of energy.

"Kilowatt" is also a rate at which energy is used. It's 1,000 joules per second, or 1,000 watts.

Answer 2

A watt is a unit of power, which is the rate of energy transfer. A second is a unit of time. Multiplying the two gives you a unit of energy, specifically a watt-second. A kilowatt is equal to 1000 watts, so a kilowatt-hour is a common unit to measure energy consumption over time.