5.1.5 Calculating Weight

• What is the formula used to calculate weight?

  Weight (W) = Mass (m) × Gravitational Field Strength (g)
• What does weight represent in physics?

  Weight is the force exerted on an object due to gravity.
• How is weight measured?

  Weight is measured in Newtons (N).
• What is mass and how is it measured?

  Mass is the amount of matter in an object, measured in kilograms (kg).
• What does gravitational field strength represent and how is it measured?


  Gravitational field strength is the strength of gravity at a location, measured in Newtons per kilogram (N/kg).
• What is the approximate value of gravitational field strength on Earth?

  On Earth, gravitational field strength is approximately 9.8 N/kg.
• What is the approximate value of gravitational field strength on the Moon?

  On the Moon, gravitational field strength is about 1.6 N/kg.
• What are the steps to calculate weight?

  1. Identify the mass (m) of the object.

  2. Determine the gravitational field strength (g) at the location.

  3. Use the formula: Weight (W) = Mass (m) × Gravitational Field Strength (g).
• If an object has a mass of 10 kg, what is its weight on Earth?

  The weight is 98 N on Earth.
• If an object has a mass of 10 kg, what is its weight on the Moon?

  The weight is 16 N on the Moon.
• What are the practical considerations regarding weight and mass?

  • Weight is the force due to gravity and is calculated using W = m × g.
  • Mass remains constant regardless of location, but weight changes with gravity.
  • Ensure mass is in kilograms and gravitational field strength is in N/kg to get weight in Newtons.
• How does weight change when moving to a different planet?

  The weight of an object varies depending on the gravitational field strength of the planet or moon.
• What is the weight of a 50 kg person on Earth?

  The weight is 490 N on Earth.
• How does the weight of a 50 kg person change if they go to Mars?

  The weight would be 185 N on Mars.
• What are the key points to remember about weight and mass?

  • Weight is the force due to gravity and is calculated using W = m × g.
  • Mass is constant, but weight varies depending on gravitational field strength.
  • Units: Mass in kilograms (kg), gravitational field strength in N/kg, and weight in Newtons (N).