Everyday Science
Understand speed, power, and energy through practical examples.
topicTry a tool
Questions and worked answers
How do you calculate average speed?
Divide total distance by total elapsed time.
How do you calculate electrical power?
For DC circuits, multiply voltage by current: P = V × I.
How do you estimate appliance energy use?
Multiply power in kilowatts by actual operating hours to estimate kilowatt-hours.
What is the difference between watts and kilowatt-hours?
Watts measure power, the rate of energy use. Kilowatt-hours measure total energy used over time.
Guides and examples
Understanding Appliance Power and Energy
Power describes how quickly a device uses energy. Energy accumulates as a device operates. A watt rating alone does not give total daily use.
Speed, Distance, and Time
Speed, distance, and time are linked by distance = average speed × time. Rearrange the equation to solve for another quantity.
Key concepts
Energy
Energy is a physical quantity associated with the capacity to do work or transfer heat. The SI unit is the joule.
Power
Power is the rate at which energy is transferred or work is done. Its SI unit is the watt.
Speed
Speed is the rate at which distance is traveled. It is a scalar quantity, so it does not include direction.
