1.1

• What is the equation for kinetic energy?

  $KE =$$\frac{1}{2} mv^2$
• What are the SI units for kinetic energy?

  Energy (J), Mass (kg), Velocity (m/s)
• What is the equation for elastic potential energy?

  $EPE =$$\frac{1}{2} kx^2$
• What are the SI units for elastic potential energy?

  Energy (J), Spring Constant (N/m), Extension (m)
• What is the equation for gravitational potential energy?

  $GPE =$$mgh$
• What are the SI units for gravitational potential energy?

  Energy (J), Mass (kg), Gravitational Field Strength (N/kg), Height (m)
• What is the definition of 'Specific Heat Capacity'?

  The amount of energy needed to raise the temperature of 1 kilogram of a substance by 1 degree Celsius.
• What are the units for Specific Heat Capacity?

  J/°C/kg
• What is the definition of 'Power'?

  The rate at which energy is transferred (or the rate at which work is done).
• What are two equations for power?

  Power = energy transferred/time and Power = work done/time
• What are the SI units for power?

  Energy (J), Work Done (J), Time (s)
• What is the unit of power?

  Watt (W)
• If Motor A lifts the same mass through the same height in half the time of Motor B, which motor dissipates more power?

  Motor A
• What are the energy changes when a ball is thrown upwards and then returns to its starting position?

  • Upwards: KE is converted to GPE
  • Peak: Maximum GPE, zero KE
  • Downwards: GPE is converted to KE
• What are the energy transfers for a bungee jumper?

  • Falling: GPE is converted to KE
  • As cord tightens: KE is converted to Elastic Potential Energy (EPE)
  • At lowest point: Initial GPE equals EPE stored in the cord
• Why does a bungee jumper slow down once the cord begins to stretch?

  Kinetic energy decreases since it is converted to elastic potential energy.
• How does the decrease in kinetic energy affect the velocity of a bungee jumper?

  As kinetic energy decreases, so does velocity.
• What are examples of chemical energy stores?

  • Food
  • Fuel (e.g., wood, coal, petrol)
  • Batteries
• What are the four different stores of energy?

  1. Kinetic Energy
  2. Gravitational Potential Energy
  3. Elastic Potential Energy
  4. Chemical Energy