Gravity and weight

• what is weight?

  the force that acts on an object due to gravity and the object’s mass
• what quantities does weight depend on?

  weight = mass x gravitational field strength

  • the object’s mass
  • the gravitational field strength at the given position in the field
• what is the unit for weight?

  the newton (N)
• what is the unit used for gravitational field strength?

  Newton per kilogram (N/kg)
• what is meant by an object’s centre of mass?

  the single point where an object’s weight can be considered to act through.
• what piece of equipment can be used to measure an object’s weight?

  • a calibrated spring-balance
  • newton-meter