Energ

    Cards (36)

    • What is a system in physics?
      An object or group of objects
    • How does energy storage change in a system?
      It changes when the system changes
    • What happens to kinetic energy when a ball hits a wall?
      • Kinetic energy is transferred as sound
      • The system is the moving ball
    • What occurs to a vehicle's kinetic energy when it slows down?
      • Kinetic energy transfers to thermal energy
      • This occurs due to friction between wheels and brakes
    • What is the formula for kinetic energy?
      Ek=E_k =12mv2 \frac{1}{2} mv^2
    • What do the variables in the kinetic energy formula represent?
      m is mass, v is speed
    • What type of energy is stored in a stretched spring?
      Elastic potential energy
    • What is the formula for elastic potential energy?
      Ee=E_e =12ke2 \frac{1}{2} ke^2
    • What do the variables in the elastic potential energy formula represent?
      k is spring constant, e is extension
    • What is the formula for gravitational potential energy?
      Ep=E_p =mgh mgh
    • What do the variables in the gravitational potential energy formula represent?
      m is mass, g is gravitational field strength, h is height
    • What is specific heat capacity?
      Energy to raise 1kg by 1°C
    • What is the formula for calculating thermal energy change?
      E=E =mcΔT mc\Delta T
    • What do the variables in the thermal energy change formula represent?
      m is mass, c is specific heat capacity, ΔT is temperature change
    • How is power defined in physics?
      Rate at which energy is transferred
    • What is the formula for power?
      P=P =Et= \frac{E}{t} =Wt \frac{W}{t}
    • What is the relationship between joules and watts?
      1 joule per second equals 1 watt
    • How can you determine which motor is more powerful?
      The one that does work faster
    • What are the ways energy can be transferred?
      • Usefully
      • Stored
      • Dissipated
      • Cannot be created or destroyed
    • What is energy dissipation?
      • Energy is stored in less useful ways
      • Often described as 'wasted' energy
    • How can lubrication reduce energy waste?
      • Reduces friction
      • Less energy lost as heat
    • How does thermal insulation help reduce energy waste?
      • Less useful thermal energy lost
      • Example: Double glazing
    • What is thermal conductivity?
      Rate at which heat travels through a material
    • How does thermal conductivity affect energy transfer in buildings?
      Higher conductivity allows faster heat transfer
    • What is the formula for efficiency?
      efficiency=\text{efficiency} =useful energy outputtotal energy input \frac{\text{useful energy output}}{\text{total energy input}}
    • How can efficiency be increased in a system?
      By reducing waste output and recycling
    • What are the main non-renewable energy sources?
      • Fossil Fuels (coal, oil, gas)
      • Nuclear Fuel
    • What are the main renewable energy sources?
      • Biofuel
      • Wind
      • Hydro-electricity
      • Geothermal
      • Tidal
      • Solar
      • Water waves
    • What is renewable energy?
      Energy that can be replenished as used
    • Why is non-renewable energy used more for large-scale supplies?
      It provides large energy output per kg
    • Why has renewable energy become more important recently?
      Due to the finite lifetime of fossil fuels
    • What are some reliability issues with renewable energy?
      Solar doesn't work at night or in bad weather
    • What are the main uses of energy?
      • Transport
      • Electricity generation
      • Heating
    • What are the environmental impacts of energy extraction and use?
      Extraction:
      • Destroys landscapes (fossil fuels)
      • Wind turbines can be eyesores
      Use:
      • Fossil fuels release harmful emissions
      • Solar and wind have no emissions
    • How did the industrial revolution affect energy use?
      • Fossil fuels became important energy sources
      • Easy to mine and provided a lot of energy
    • What challenges exist in using energy resources today?
      • Increasing public power demands
      • Environmental issues are complex
      • Political, social, ethical, and economic considerations
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