Energy

• What must you be able to describe regarding energy storage in a system?

  Changes in the way energy is stored
• What is required to calculate energy changes in a system?

  Calculate the energy changes involved
• What does internal energy refer to?

  Total kinetic and potential energy of particles
• How do you use specific heat capacity in calculations?

  In calculations involving temperature changes
• What is a system in physics?

  An object or group of objects
• How does a roller coaster demonstrate energy transfer?

  Transfers energy between gravitational and kinetic energy
• What is the formula for kinetic energy?

  $KE =$$0.5 \times m \times v^2$
• How do you calculate gravitational potential energy?

  $GPE =$$m \times g \times h$
• What is the formula for elastic potential energy?

  $EPE =$$0.5 \times k \times x^2$
• What happens to internal energy when work is done on a system?

  It increases the energy stored in the system
• How is kinetic energy measured?

  In joules (J)
• What is the unit for mass?

  Kilograms (kg)
• How is speed measured?

  In metres per second (m/s)
• What is the unit for gravitational potential energy?

  Joules (J)
• What is the unit for gravitational field strength?

  Newtons per kilogram (N/kg)
• How is height measured?

  In metres (m)
• What is the unit for elastic potential energy?

  Joules (J)
• What is the unit for spring constant?

  Newtons per metre (N/m)
• How is extension measured?

  In metres (m)
• What is specific heat capacity?

  Energy required to raise temperature of 1 kg by 1°C
• How do you calculate change in thermal energy?

  $\Delta E =$$m \times c \times \Delta \theta$
• What is the increase in temperature when 2100 J is provided to 100 g of water?

  5°C
• What is the method to investigate specific heat capacity of materials?

  1. Set up apparatus
  2. Measure start temperature
  3. Switch on heater for 1 min
  4. Measure end temperature
  5. Measure potential difference and current
  6. Repeat for different liquids
  7. Calculate specific heat capacity
  8. Compare results for reproducibility
• What is the independent variable in the specific heat capacity investigation?

  The type of liquid
• What is the dependent variable in the specific heat capacity investigation?

  The temperature
• What are control variables in the specific heat capacity investigation?

  Amount of liquid and energy provided
• What is an anomalous result?

  A result that doesn't fit the pattern
• Why is it important to identify anomalous results?

  To determine the cause of discrepancies
• What is the main hazard in the specific heat capacity investigation?

  Hot water can cause scalds
• What happens if water spills on insulating material?

  It will affect the results
• What are the two categories of energy resources?

  Renewable and non-renewable
• What is a key point about energy transfer in a closed system?

  Total energy never changes, only transfers
• How does a lift demonstrate energy transfer?

  Transfers electrical energy into gravitational potential energy
• What causes wasted energy?

  Unwanted energy transfers
• How can unwanted energy transfers be reduced?

  Using lubrication and thermal insulation
• What affects the rate of cooling in a building?

  Thickness and thermal conductivity of walls
• What is the main hazard when using hot water in experiments?

  It can scald
• What is the purpose of the required practical on thermal insulators?

  To compare effectiveness of different insulation materials
• What is the environmental impact of biofuels?

  Large areas of land needed for crops
• What is a disadvantage of wind energy?

  Turbines can be noisy and dangerous to birds