Weight, Mass and Gravity

• What is gravitational force?

  Force of attraction between masses
• Why do we notice gravity primarily with large masses?

  Because they create a significant pull
• What does gravity cause all things to do?

  Fall towards the ground
• What are the two important effects of gravity on a planet's surface?

  • Causes all things to fall towards the ground
  • Gives everything weight
• What is mass?

  Amount of 'stuff' in an object
• How does weight differ from mass?

  Weight is the force due to gravity
• What does weight depend on?

  Gravitational field strength at a location
• How does gravitational field strength change with distance from a mass?

  It is stronger the closer you are
• How does weight change when moving from Earth to the Moon?

  It weighs about 1/6 on the Moon
• What is the weight of a 1 kg object on the Moon?

  About 1/6 of its weight on Earth
• In what units is weight measured?

  Newtons
• What is the center of mass in an object?

  Point where force acts on the object
• How is weight measured?

  Using a calibrated spring balance
• How is mass measured?

  In kilograms with a mass balance
• What is the relationship between mass and weight?

  • Mass and weight are directly proportional
  • Weight = Mass x Gravitational field strength (N/kg)