Gravity and Weight

• What is gravity?

  The force of attraction between all objects. It is a non-contact force as the two objects do not need to be touching.
• Is gravity a vector or scalar quantity?

  Vector because it has a magnitude and a direction.
• What is mass?

  Tells us how much matter the object has in it.
• What is the unit for mass?

  Kg
• Is mass a vector or scalar quantity?

  Scalar because it has no direction.
• Does the mass depend on where an object is?

  The mass does not depend on where an object is, it does not change.
• What is weight?

  The force acting on an object due to gravity.
• What is the unit for weight?

  Newton (N)
• Does the Weight of an object depend on where it is?

  Yes the weight of an object depends on where it is, the weight of an object on Earth will be different on other planets e.g Jupiter 24.7N/Kg
• How do you calculate weight?

  Weight (N) = Mass (Kg) X gravitational field strength (N/Kg)
• Is the weight of an object directly or indirectly proportional to the mass of the object?

  Directly proportional, this means if we double the mass, the weight also doubles.
• How can we determine an objects weight?

  By using a calibrated spring-balance also called a newtonmetre.
• What is gravitational field strength?

  The measure of the force of gravity in a particular location. Weight depends on where you are.
• Where does the weight of an object act?

  It is considered to act at a single point, called the centre of mass.