Gravity, Mass and Weight

• Weight calculation

  Weight = Mass x Gravitational field strength
• Gravitational field strength

  • For Earth: 9.8 newtons per kilo
  • For the Moon: 1.6 newtons per kilo
• Mass and weight are two different things in physics, with mass being an intrinsic property of an object and weight being the force acting on it in a gravitational field
• Gravitational field


  Field of influence around an object due to gravity
• Gravitational potential energy is measured in joules
• Gravitational potential energy

  Energy transferred to an object's gravitational potential energy store when lifting it against gravity
• Weight is the force of attraction an object experiences in a gravitational field
• Gravitational field strength

  Strength of the gravitational field, denoted by the letter g
• Example calculation for gravitational potential energy: Mass = 0.1 kg, Gravitational field strength = 9.8 N/kg, Height = 3 m, Result = 2.94 joules
• Gravitational potential energy formula

  Ep = Mass x Gravitational field strength x Height
• Energy required to lift an object


  Energy or work is needed to overcome the force of gravity
• Key takeaways: Gravity is a force of attraction between objects, weight is equal to mass times gravitational field strength (9.8 N/kg on Earth), and gravitational potential energy is denoted by Ep and equals mass times gravitational field strength times height
• Gravity


  Force of attraction between two objects with the size of that force depending on the mass of those two objects and how far apart they are