P5a

• What does a free body diagram show?

  Magnitude and direction of forces
• What force does the object in the diagram experience?

  5N to the left
• What does it mean to resolve forces?

  Split a force into two components
• What do combined forces have?

  The same effect
• What are the units for force, mass, and distance?

  • Force: newton (N)
  • Mass: kilogram (kg)
  • Distance: metre (m)
• What is a kilonewton (kN)?

  1,000 newtons
• What is a meganewton (MN)?

  1,000,000 newtons
• How is velocity defined?

  Speed in a given direction
• What is displacement?

  Distance in a given direction
• What is the centre of mass?

  Point through which weight acts
• What is the difference between scalars and vectors?

  • Scalars: Only have magnitude (e.g., mass, time)
  • Vectors: Have magnitude and direction (e.g., force, velocity)
• What does the length of an arrow represent in vectors?

  Size of the vector
• What does the direction of an arrow represent in vectors?


  Direction of the vector
• What can a force be described as?

  A push or a pull
• What are contact forces?

  Forces exerted when objects touch
• What are non-contact forces?

  Forces exerted without touching
• What is a resultant force?

  Single force with the same effect
• How do you combine two forces acting in the same direction?

  Add them together
• How do you combine two forces acting in opposite directions?

  Take them away
• What happens when work is done?

  Energy is transferred
• What is the formula for work done?

  Work done = force x distance
• How much work is done when 1N moves an object 1m?

  1 joule of work
• When is no work done?

  If force is at right angles to movement
• What happens if work is done against friction?

  Thermal energy store increases
• What can forces do to an object?

  Accelerate or deform it
• What is elastic deformation?

  Stretched but returns to original length
• What is inelastic deformation?

  Stretched and cannot return
• How is extension calculated?

  Current length – original length
• What does Hooke's law state?

  Extension is directly proportional to force
• What is the limit of proportionality?

  Point where force-extension graph is not straight
• What is elastic potential energy?

  Energy stored in a stretched spring
• What happens when work is done on a spring?

  Increases elastic potential energy store
• What is the formula for Hooke's law?

  F = k x e
• What is the formula for elastic potential energy?

  E = ½ x k x e²
• What is mass?

  How much matter something is made of
• How is weight measured?

  In newtons (N)
• What is weight?

  Force acting on an object due to gravity
• What is gravitational field strength?

  Weight experienced per kilogram of mass
• What is the gravitational field strength on Earth?

  9.8 N/kg
• What is the formula for weight?

  W = m x g