Physics - Energy 0.0 / 5 ? PhysicsEnergyGCSEAQA Created by: feivellb._Created on: 13-11-20 17:36 A system A system is an object or group of objects. 1 of 24 Types of energy stores magnetic, internal (thermal), chemical, kinetic, electrostatic, elastic potential, gravitational potential, nuclear 2 of 24 Closed system Neither matter nor energy can enter/leave. The net change in the total energy of a closed system is ALWAYS ZERO 3 of 24 How is energy transferred? Energy is transferred by stores. When energy is transferred to an object, the energy is stored in one of the object's energy stores. 4 of 24 Formula for Work Done W = Fd OR Work Done (J) = Force (N) x Distance (m) 5 of 24 What does Kinetic Energy depend on? KE depends on an object mass and speed. The greater the mass and the faster it's going, the more energy there will be 6 of 24 Formula for Kinetic energy KE = 1/2 mv OR Kinetic energy (J) = 1/2 x mass (kg) x speed (m/s) 7 of 24 What does Gravitational Potential Energy depend on? GPE depends on object's mass, height and grav. field strength. The HIGHER the object is lifted, the more energy is transferred to this store. 8 of 24 Formula for Gravitational Potential Energy GPE = mgh OR Gravitational Potential Energy (J) = mass (kg) x grav. field strength (N/kg) x height (m) 9 of 24 Formula for Elastic Potential Energy Ee = 1/2 ke OR Elastic Potential Energy (J) = 1/2 x Spring Constant (N/m) x Extension (m) 10 of 24 What is Specific Heat Capacity? The amount of energy required to change the temperature of 1kg of a substance by 1°C 11 of 24 Formula for Specific Heat Capacity E=mcΔT OR Energy (J) = mass(kg) x Specific Heat Capacity(J/kg°C) 12 of 24 What is Power? The rate of energy transfer/rate of doing work 13 of 24 What unit is Power measured in? Watts (W) 14 of 24 What is one Watt equal to? One Watt = One Joule transferred per second OR W = J/s 15 of 24 Formula for Power P = E/t OR P = W/t OR Power (W) = Energy Transferred (J) ÷ time (s) 16 of 24 What is the Conservation of Energy? Energy can be transferred usefully, stored or dissipated, but can NEVER be CREATED or DESTROYED 17 of 24 Formula for Efficiency Useful output energy transfer/Total input energy transfer OR Efficiency = Useful Power output /Total power input 18 of 24 Methods to reduce unwanted Energy Transfers Lubrication and Insulation 19 of 24 Non-Renewable Energy Resources will... ...RUN OUT one day 20 of 24 What are non-renewable energy sources? They are fossil fuels and nuclear fuel (e.g. uranium and plutonium) 21 of 24 What are the three main fossil fuels? Coal, Oil, Natural gas 22 of 24 Renewable Energy Resources will... ...NEVER Run Out 23 of 24 Examples of Renewable energy sources The Sun (Solar), Wind, Water waves, Hydro-electricity, Bio-fuel, Tides, Geothermal 24 of 24
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