physics combined

• What happens to the total energy in a closed system during energy transfers?


  There is no net change to the total energy in that system.
• What are the different ways that the energy of a system can be changed?

  Through work done by forces, in electrical equipment, and in heating.
• How is work done by a force measured?


  Work done by a force is measured in joules (J) and is equal to energy transferred.
• What is the equation for work done?

  Work done (joule, J) = force (newton, N) × distance moved in the direction of the force (metre, m).
• How do you calculate the change in gravitational potential energy when an object is raised?


  Change in gravitational potential energy (joule, J) = mass (kilogram, kg) × gravitational field strength (newton per kilogram, N/kg) × change in vertical height (metre, m).
• What is the equation for kinetic energy?


  Kinetic energy (joule, J) = \(\frac{1}{2} \times \text{mass (kilogram, kg)} \times (\text{speed})^2\).
• How is energy dissipated in system changes?


  Energy is dissipated so that it is stored in less useful ways.
• What happens to mechanical processes that cause a rise in temperature?


  They become wasteful by dissipating energy in heating the surroundings.
• How is power defined in physics?


  Power is defined as the rate at which energy is transferred.
• What is the equation for power?

  Power (watt, W) = work done (joule, J) ÷ time taken (second, s).
• What is one watt equivalent to?


  One watt is equal to one joule per second (J/s).
• What is the equation for efficiency?


  Efficiency = (useful energy transferred by the device) ÷ (total energy supplied to the device).
• What is the importance of using ratios and proportional reasoning in calculations?


  It helps convert units and compute rates.
• What is the focus of Topic 9 in the specification?


  Forces and their effects.
• How can objects interact at a distance?

  Through gravitational, electrostatic, and magnetic fields.
• What is the difference between vector and scalar quantities?


  Vector quantities have both magnitude and direction, while scalar quantities have only magnitude.
• How can vector diagrams be used in physics?


  To illustrate resolution of forces, net force, and equilibrium situations.
• What is a free body force diagram used for?


  To draw and use representations of forces acting on an object.
• What happens when several forces act on an isolated solid object?


  They can lead to a resultant force on the object.
• How can unwanted energy transfer be reduced?


  Through lubrication.
• What is the title of Topic 10 in the specification?


  Electricity and circuits.
• What should students describe regarding the structure of the atom?

  The position, mass, and charge of protons, neutrons, and electrons.
• What is the purpose of electric circuit diagrams?


  To represent circuits with positive and negative terminals and various components.
• What is the difference between series and parallel circuits?


  Series circuits have components connected in a single path, while parallel circuits have multiple paths for current.
• How is a voltmeter connected in a circuit?


  A voltmeter is connected in parallel with a component.
• What does potential difference (voltage) represent?


  It is the energy transferred per unit charge passed.
• What is the equation for energy transferred in terms of charge and potential difference?


  Energy transferred (joule, J) = charge moved (coulomb, C) × potential difference (volt, V).
• How is an ammeter connected in a circuit?


  An ammeter is connected in series with a component.
• What is electric current defined as?


  Electric current is the rate of flow of charge.
• What is the equation for charge in terms of current and time?


  Charge (coulomb, C) = current (ampere, A) × time (second, s).
• What happens when a closed circuit includes a source of potential difference?


  There will be a current in the circuit.
• What is the principle of current conservation at a junction in a circuit?


  Current is conserved at a junction in a circuit.
• How does changing resistance in a circuit affect current?


  Changing resistance affects the current, which can be achieved using a variable resistor.
• What is the equation for potential difference in terms of current and resistance?


  Potential difference (volt, V) = current (ampere, A) × resistance (ohm, Ω).
• What happens to net resistance when resistors are in series?


  The net resistance is increased.
• What happens to net resistance when resistors are in parallel?


  The net resistance is decreased.
• What is the focus of Topic 12 in the specification?


  Magnetism and the motor effect.
• What happens to unlike magnetic poles?


  Unlike magnetic poles attract.
• What are examples of permanent and temporary magnetic materials?


  Permanent materials include cobalt, steel, iron, and nickel.
• What is the difference between permanent and induced magnets?


  Permanent magnets maintain their magnetism, while induced magnets only become magnetic in the presence of a magnetic field.