physics

• energy transfer
• system as an object or a group of objects
• the work done on a system is equal to energy transferred into the system plus energy transferred out of the system
• describe how energy changes involved in a energy transfer
• work done = force x distance moved by object doing work
• power = rate at which energy is transferred
• power = work done / time taken
• rate of change of energy stored in a system = power
• average power = total energy transferred / time taken
• energy transfer diagrams
• energy cannot be created or destroyed only transferred
• efficiency = (useful output) / (input)
• the efficiency of an engine can be calculated using the equation e = useful output / input x 100%
• power is measured in watts, where one joule per second equals one watt
• one way thta we can reduce energy transfer by using thermal conductivity is by using insulation as it traps the heat
• Efficiency

  A measure of how much useful output is produced relative to the input consumed. Calculated as the ratio of useful output to input (efficiency = useful output / input).
• renewable energy
• non renewable energy
• solar power can generate electricity by using the sun
• wind power
• fossil fuels
• coal is a non renewable resource
• snakey diagrams used to show energy transfer of useful and wasted output
• energy we put into something must be the same amount coming out
• energy efficiency = useful output / total input x 100%
• efficiency being able to do a task without wasting energy or time
• work done = force * distance moved
• energy can be transfered by surrounding objects
• lubrication used to reduce wasted energy
• hydro power uses water falling from dams to turn turbines which generate electricity
• dissipitation loss of energy when something cools down
• geothermal power is using hot rocks deep underground to create steam that drives turbines
• density is the substance mas per unit or volume.it tells us how tightly matter is packed together
• density =mass*volume
• mass =density
• solid is a strong force of attraction between particles in a fixed regular arrangement
• liquid particles have more kinetic energy thansolid particles
• when a liquid changes to a solid its density decreases
• displacement can used to measure the volume of a irregular object
• to measure the volume of a irregular object you fill the displacement can with water the slowly add the object to the water he water then get a measuring cylinder to catch the water