Gravity and weight

• How can gravity be defined?

  As a force of attraction between two objects
• What factors determine the size of the gravitational force?

  The mass of the objects and their distance apart
• Why is the gravitational force of small objects negligible?

  Because they have relatively low masses
• How does distance affect gravitational force for large objects?

  Gravitational force decreases with increased distance
• What is the gravitational field around an object called?

  Gravitational field
• What symbol represents gravitational field strength?

  The letter g
• What is the gravitational field strength on Earth?

  Approximately 9.8 newtons per kilo
• What is the gravitational field strength on the Moon?

  Approximately 1.6 newtons per kilo
• What happens to an object in a gravitational field?

  It experiences a force of attraction
• How is weight defined in physics?

  As the force of attraction on an object
• How do you calculate an object's weight?

  Mass times gravitational field strength
• What is the weight of a person with a mass of 60 kilos on Earth?

  588 newtons
• Why do we often say we weigh 60 kilos instead of having a mass of 60 kilos?

  Because of differences in technical terms
• What is the difference between mass and weight?

  Mass is intrinsic; weight is a force
• What is required to lift an object against gravity?

  Energy or work
• What is the formula for gravitational potential energy?

  ep = mgh
• What units are used for gravitational potential energy?

  Joules
• How do you convert grams to kilos?

  Divide by 1000
• What is the gravitational potential energy of a 100-gram apple thrown 3 meters up?

  2.94 joules
• What are the key takeaways about gravity, weight, and gravitational potential energy?

  • Gravity is a force of attraction.
  • Weight = mass × gravitational field strength (9.8 N/kg on Earth).
  • Gravitational potential energy (ep) = mass × gravitational field strength × height.