(P1) Topic 3- Conservation Of Energy Flashcards
What are the eight main stores of energy
Magnetic, thermal, chemical, kinetic, electrostatic, elastic potential, gravitational potential, nuclear
Conservation of energy
Energy cannot be created or destroyed. It can only be transferred, stored, or dissipated
What are the four main ways of transferring energy
Mechanical work- a force moving an object through a distance
Electrical work- charges moving due to a potential difference
Heating- due to temperature difference cause electrically or by chemical reaction
Radiation- energy transferred as a wave, e.g light and infrared- the sun emits light radiation and infrared radiation
What does dissipated mean in terms of energy
Wasted, usually by being lost to the surroundings
Where can energy go in a closed system
It is only transferred within that system. There is no net change in the total energy of the whole system
Calculation for change in GPE
Change in GPE= mass x gravitational field strength x change in vertical height
Calculation for kinetic energy
Kinetic energy= 1/2 x mass x velocity^2
What is one way of reducing the amount of energy dissipated through friction
Lubrication- reduces fiction between moving parts
How can wasteful dissipation of thermal energy from an item that is designed to transfer thermal energy be decreased
Thermal insulation
Calculation for efficiency
Efficiency= useful energy transferred / total energy supplied
Calculation for percentage of efficiency
Percentage efficiency= (useful energy transferred / total energy supplied) x 100
What are reasons that devices waste energy
Friction between moving parts, electrical resistance, sound energy
What are the major energy resources available to produce electricity
Fossil fuels, nuclear fuel, biofuel, wind, hydroelectricity, geothermal, tidal, water waves, the Sun
What does burning fossil fuels produce
Carbon dioxide (adds to greenhouse effect) and sulfur dioxide (causes acid rain)
How are renewable resources replenished
Human action and natural processes