knowledge base

How much is m/s^2

• It means we have an increase in speed of 1m/s in 1 second.
• For 10m/s^2 for 60 seconds means
  • Speed of an object increases by 10 m/s every second for a duration of 60 seconds.
  • In the end, the object will have a speed of 600m/s.
• Acceleration due to gravity on earth in 9.8m/s^2
  • It means if you’re falling from a height, your speed will increase by 9.8m/s every second.
  • If one fall from building from 1 km height, when you reach the ground, you will have a speed of 98m/s.
  • For comparison, Usain Bolt’s top speed is ~10m/s.

How much is 1 Newton

• 1N is the force required to accelerate a 1kg mass at 1m/s^2.
• For 60kg of human, the force applied on Earth is approximately 588.6 N
  • 60kg * 9.8m/s^2 = 588.6N

How much is 1 Joule

• Amount of energy to move 1kg mass at 1m/s^2 for 1 m distance.
• Picking up 100 gm apple from ground to table(at 1m height) is ~1J of work.
  • 0.1kg * 9.8m/s^2 * 1m = 0.98J

How much is 1 Watt

• Amount of power needed to move 1kg mass at 1m/s^2 for 1 m distance in 1 second.
• Same apple example, if you pick up 100 gm apple from ground to table(at 1m height) in 2 second then
  • Joule = 0.1kg * 9.8m/s^2 * 1m = 0.98J
  • Watt = 0.98J / 2(second) = 0.49W
  • It means you need 0.49W power to pick up apple in 2 seconds at 1m height.
• For 100W light bulb,
  • Power = 100W == 100J/s
  • Time = 2 hour
  • Energy = 100W * 2h == 200Wh

What is Watt-hour

• Watt-hour is the unit of energy?
• 1 watt-hour is equal to 1 watt of power sustained for 1 hour (1 Wh = 1 W × 1 h = 3600 joules).
• 100-watt light bulb
  • Time = 2 hour
  • Energy = 100W * 1h = 100Wh = 0.1KWh
• For AC with with 2000Wh
  • Time = 1 hour
  • Power = 2000W
  • Energy = 2000W * 1h = 2000Wh = 2KWh = 2 units

What is kilowatt-hour

• 1 Kwh is 1000 watt-hour.
• Commonly used unit of energy for electricity, also called “unit” in India.
• For AC with 2 Kwh, it means 2000W power sustained for 1 hour.
  • For every hour, it consumes 2 Kwh of energy.