Basic physics
Average speed is distance divided by time. Electric energy is power times time, which is why power bills charge in kWh.
About: Basic physics
Average speed is distance divided by time. Electric energy is power times time, which is why power bills charge in kWh.
Worked examples
What is the SI unit of force?
Answer: Newton (N). Joules measure energy and watts measure power. Force is measured in newtons.
A car travels 120 km in 2 hours. What is its average speed?
Answer: 60 km/h. Average speed = distance ÷ time = 120 ÷ 2 = 60 km/h.
At high altitude, water boils:
Answer: Below 100 °C. With lower air pressure, water needs less energy to boil.