CP7-8

• What is the equation for work done?

  Work done = force x distance
• Why is the distance important in the work done equation?

  It is the distance moved in the direction of the force
• How is power defined?

  Power is the rate of doing work
• What is the equation for power?

  Power = work done / time taken
• What is the unit for power?

  Watt (W)
• Name two contact forces.

  Friction and air resistance
• Name two non-contact forces.

  Gravity and magnetism
• What is a field?

  A space around an object where something else feels a force
• How are forces represented?

  As vectors – arrows showing direction and magnitude
• How would you draw a free body force diagram for a car travelling at a steady speed?

  Equal sized arrows for engine force and drag
• How do you find the resultant if forces are not acting along the same line?

  Draw a scale diagram and use a parallelogram
• What does resolving forces mean?

  Splitting the resultant force into vertical and horizontal parts
• What are the steps to draw a free body force diagram?

  • Identify all forces acting on the object
  • Represent each force as an arrow
  • Ensure arrows are proportional to the force's magnitude
  • Label each force clearly
• What type of forces occur when objects are touching each other?

  Contact forces
• What are the types of forces and their classifications?

  • Contact Forces:
  • Friction
  • Air resistance
  • Thrust
  • Upthrust
  • Water resistance
  • Lift
  • Drag
  • Normal (contact/reaction)
  • Non-contact Forces:
  • Gravity
  • Magnetism
  • Static electricity
• What type of forces occur when objects are not touching each other?

  Non-contact forces
• Why do non-contact forces occur?

  Because there is a field around an object
• How can forces be represented visually?

  By arrows showing magnitude and direction
• What happens when energy is transferred in an electric light bulb?

  Electricity transfers to the bulb, then to surroundings
• What is work done in physics?

  Energy transferred when a force moves something
• What is power in the context of energy transfer?

  The rate at which energy is transferred
• How is power measured?

  In Watts (W)
• What does 1 Watt represent?

  1 joule of work done per second
• What happens when the forces acting on a body are balanced?

  The resultant force on the object is zero
• How can we find the resultant force when forces are not acting along the same line?

  By drawing a scale diagram
• What can we do if we know the size of the resultant forces?

  Work out the size of the upwards and sideways force
• What does it mean to resolve forces?

  To break them into two components
• How can we resolve forces besides using scale diagrams?

  By using mathematical calculations
• What particles make up atoms?

  Protons, neutrons, and electrons
• How big are atoms?

  Atoms are very small
• How has our model of the atom changed over time?

  It evolved from simple to complex models
• How are atoms and molecules often modeled?

  As spheres
• What is the plum pudding model of the atom?

  A model with positive material and electrons
• What does particle theory explain?

  The properties of solids, liquids, and gases
• What do we call the particles that make up substances?

  Atoms
• What occurs during chemical reactions?

  Atoms join in different ways
• How does particle theory explain solids have a fixed shape?

  Particles are closely packed and vibrate
• Who conducted experiments showing atoms contain electrons?

  J.J. Thomson
• What charge do electrons have?

  Negative charge
• What did Thomson's new model describe the atom as?

  A pudding with scattered electrons