Physics revision – CHAPTER 1 – Energy Potential energy Work done and energy transfer When a spring is stretched it stores _________. We call this _______________________. When a string is stretched it stores ________________ energy. When a box is lifted above the ground it gains ______________________________ energy (GPE). What two things does GPE depend on? _______________________________________________________ In Science, __________ is only done by a force when an object ___________. Work done can be calculated using the equation: W=Fs W is __________ joules ___ F is ___________ newtons ___ s is ___________ metres ___ Example: A gymnast weighs 400N. How much work does she do when she jumps from the ground onto a beam 1.5 m above the ground? ____________________________________ Rearrange the equation to make force the subject. __________________ Understanding power Kinetic energy _________ is the rate of doing work or _____ transfer. Write the 2 equations for power. _______________________ A machine does 1000J of work in 8 seconds. What power does it develop? An electric kettle is rated at 2kW. How much energy is transferred in 30s? Energy must be transferred to make things move. This is called _____________ energy. What is the equation for kinetic energy? _______________ Use the kinetic energy equation to answer the following question: Sue is riding her bicycle at 2m/s, she has a mass of 50kg. Calculate her kinetic energy. _______________________________________________________________________________________ KEY WORDS: Potential energy Gravitational potential energy Kinetic energy Work Force Power Energy transfer ASSESSMENT:

Physics revision – CHAPTER 1 – Energy cont… COMMON MISCONCEPTION Energy efficiency Dissipation of energy Look at the picture, where is most thermal energy lost? __________________ Explain how you could reduce this unwanted energy transfer. ________________________________________________________________________ In the box write the 2 efficiency equations. Heating and temperature are not the same thing. When something is heated, thermal energy is being transferred to it. Temperature is a measure of how hot or cold something is. Using energy resources List all of the non-renewable energy recourses used to generate electricity. ____________________________________________________________________________________________________ List all of the renewable energy recourses used to generate electricity. Most of the energy resources available to us store energy that has originally come from __________________. These include fossil fuels (____, ____ and ____), bio-fuel, wind, wave, hydroelectric and solar energy. Other resources include geothermal energy (from hot,_______________), tidal energy and nuclear energy. MAKING LINKS The idea that energy can be transferred usefully, stored or dissipated without changing the total amount of energy is a key concept in Science. You will use this idea in many contexts, and not just in Physics. ASSESSMENT: KEY WORDS: conduction energy dissipation radiation energy efficiency conservation of energy non-renewable  resource renewable resource 2

Physics revision – CHAPTER 1 – Energy - Answers Potential energy Work done and energy transfer When a spring is stretched it stores __energy____. We call this ______potential energy____. When a string is stretched it stores _____elastic potential____ energy. When a box is lifted above the ground it gains ____gravitational potential____ energy (GPE). What two things does GPE depend on? ____Mass, m, in kilograms.____ _____Height the box raises, h, in metres, m._____ In Science, _work_ is only done by a force when an object _moves_. Work done can be calculated using the equation: W=Fs W is _Work in _ joules _J_ F is _Force in _ newtons _N_ s is _distance in _ metres _m_ Example: A gymnast weighs 400N. How much work does she do when she jumps from the ground onto a beam 1.5 m above the ground? _W=Fs W=400x1.5 W= 600J_ Rearrange the equation to make force the subject. _F = W/s_ Understanding power Kinetic energy _Power_ is the rate of doing work or _energy_ transfer. Write the 2 equations for power. _P = W/t or P = E/t_ A machine does 1000J of work in 8 seconds. What power does it develop? _P = W/t = 1000/8 = 125W_ An electric kettle is rated at 2kW. How much energy is transferred in 30s? _E=Pt = 2000 x 30 = 60000J_ Energy must be transferred to make things move. This is called ___kinetic___ energy. What is the equation for kinetic energy? ____1/2 mv2____ Use the kinetic energy equation to answer the following question: Sue is riding her bicycle at 2m/s. she has a mass of 50kg. Calculate her kinetic energy. _1/2 mv2 = 0.5 x 50 x 2 x 2 = 100J_ KEY WORDS: Potential energy Gravitational potential energy Kinetic energy Work Force Power Energy transfer ASSESSMENT:

Physics revision – CHAPTER 1 – Energy cont……Answers COMMON MISCONCEPTION Energy efficiency Dissipation of energy Look at the picture, where is most thermal energy lost? __Through the walls.__ Explain how you could reduce this unwanted energy transfer. __Adding insulation. This will cut down on the transfer of energy by conduction and radiation.______ Heating and temperature are not the same thing. When something is heated, thermal energy is being transferred to it. Temperature is a measure of how hot or cold something is. In the box write the 2 efficiency equations. useful output energy transfer total input energy transfer AND useful power output total power input Using energy resources List all of the non-renewable energy recourses used to generate electricity. ___Coil, oil, natural gas and nuclear___ List all of the renewable energy recourses used to generate electricity. ___hydroelectric, wave, tidal, solar, wind, bio gas, bio diesel. ______ Most of the energy resources available to us store energy that has originally come from __the Sun ___. These include fossil fuels ___(coal, oil and gas)__, bio-fuel, wind, wave, hydroelectric and solar energy. Other resources include geothermal energy (from hot, underground rocks), tidal energy and nuclear energy. MAKING LINKS The idea that energy can be transferred usefully, stored or dissipated without changing the total amount of energy is a key concept in Science. You will use this idea in many contexts, and not just in Physics. ASSESSMENT: KEY WORDS: conduction energy dissipation radiation energy efficiency conservation of energy non-renewable  resource renewable resource 4