forces

• What is a scalar quantity?

  A quantity with only magnitude
• How do vector quantities differ from scalar quantities?

  Vectors have both magnitude and direction
• How can the direction of a vector be represented?

  As a written description or an arrow
• What does the length of an arrow in a vector diagram represent?

  The magnitude of the quantity
• What are the types of contact forces?

  • Reaction force
  • Tension
  • Friction
  • Air resistance
• What is a contact force?

  Forces acting between touching objects
• What is a reaction force?

  Force experienced by an object at rest
• What is a tension force?

  Force experienced by a stretched object
• What is a friction force?

  Force between sliding objects
• What is air resistance?

  Force acting on an object moving through air
• What does Newton's Third Law of Motion state?

  For every action, there is an equal reaction
• What are the types of non-contact forces?

  • Magnetic force
  • Electrostatic force
  • Gravitational force
• What is a non-contact force?

  Forces acting between non-touching objects
• What is a magnetic force?

  Force experienced by magnetic materials
• What happens to opposite magnetic poles?

  They attract each other
• What happens to like magnetic poles?

  They repel each other
• What is an electrostatic force?

  Force experienced by charged particles
• What happens to opposite charges?

  They attract each other
• What happens to like charges?

  They repel each other
• What is a gravitational force?

  Force experienced by masses in a field
• What happens to masses in a gravitational field?

  They are attracted towards each other
• What do all objects with mass produce?

  A gravitational field
• How does mass affect gravitational field strength?

  The greater the mass, the stronger the field
• What is the unit of weight?

  Newtons (N)
• How is weight measured?

  Using a calibrated spring-balance
• Why is weight considered a non-contact force?

  It acts through a gravitational field
• What is the gravitational field strength of Earth?

  9.8 N/kg
• What happens to weight in a weaker gravitational field?

  The weight of an object is smaller
• What is the gravitational field strength of the Moon?

  1.6 N/kg
• How does an astronaut's weight on the Moon compare to Earth?

  They weigh less on the Moon
• What point does the weight of an object act at?

  Its centre of mass
• How are weight and mass related?

  Weight is directly proportional to mass
• What is the equation to calculate weight?

  weight = mass × gravitational field strength
• What are the units for weight, mass, and gravitational field strength?

  N, kg, N/kg respectively
• What is work defined as?

  Energy transferred from one store to another
• When is work done against frictional forces?

  When an object's temperature increases
• What does a free body diagram represent?

  The forces acting on an object
• How is an object represented in a free body diagram?

  As a box or a dot
• Why is it important to label arrows in free body diagrams?

  To show the magnitude of the force
• What can two forces be combined to find?

  A resultant force