Energy-Paper 1 Flashcards
How energy is Transferred?
When energy is transferred to an object, the energy is stored in one of the object’s energy stores.
What are the 8 energy stores?
1)Thermal energy stores
2) Chemical energy stores
3) Kinetic energy stores
4) Magnetic energy stores
5)) Gravitational potential energy stores
6) Electrostatic energy stores
7) Elastic potential energy stores
8) Nuclear energy stores
What are the Transfers of energy? (4)
Energy is transferred:
-mechanically (WD force)
-electrically (WD moving charges)
-heating
-radiation
When a System Changes why?
What is a closed system?
.A system=single object or a group of objects (e.g. two colliding vehicles)
1)system changes, energy is transferred. transferred into or away system, different systems or energy stores.
2)Closed systems=neither matter nor energy can enter or leave. Net change=0
Kettle example Energy can be Transferred by Heating? (Systems)
.boiling water in a kettle - water as system.
-Energy transferred to water (from kettle’s heating element)
-heating, water’s thermal energy store ( temperature water rise)
What is work done and an example when a current flows through a circuit and forces?
.Work Work done=energy transferred
.current flows (work done against resistance in a circuit)
.force moving an object
A ball is through up what energy transfers occur? (3)
1)initial force exerted by a person to ball through up a height is accelerated. It causes by gravity. gravitational force does work.
2)energy transfer from the chemical causes energy to be transferred from energy store of the person’s arm to the ball’s gravitational potential energy
3)kinetic energy store of the ball and arm.
Friction between a car and its brakes to slow down? 2
1.energy to be transferred from car’s kinetic energy store to
2.elastic potential and thermal energy stores of the object+ car body because of friction
1)What does Movement Mean?
2)what does the kinetic energy store depend on?
3)what is the KE dependent on? 2
1)energy in kinetic energy store.
2)Energy transferred store object speeds up transferred away store object slows down.
3)
=depends:
object’s mass, speed.
greater mass = faster= more energy
How do Raised Objects Store Energy in Gravitational Potential Energy?
How much GPE store depends on what? 3
1)Lifting object gravitational field requires transfer energy to the gravitational potential energy store.
2)mass, height, strength of gravitational field the object is in.
3) GPE(J)=Mass(KG)xGFS(N/KG)xHEIGHT(m)
How do Falling Objects Transfer Energy process? 3
1) energy from gravitational potential energy store transferred to kinetic energy store.
2) falling object when there’s no air resistance: Energy lost g.p.e. store = gained kinetic energy store
3) air resistance acts against all falling objects= energy to be transferred energy stores,(thermal energy)
How does Stretching Transfer Energy to Elastic Potential Energy Stores? 2
1)Stretching/squashing object=transfer energy to elastic potential energy store.
2)limit of proportionality has not been exceeded
EPE(J)=1/2xSpring constant (N/M) x Extension^2 (m)
1)What is specific heat capacity?
2)How and why do Different Materials Have Different Specific Heat Capacities?
1)amount of energy needed to raise the temperature of 1 kg of a substance by 1°C.
1-energy transferred to the thermal energy store materials increase temp
2-Materials that need to gain lots energy thermal energy stores warm up transfer loads of energy when cool down.
How to Investigate Specific Heat Capacities?
1) solid material (e.g. copper), block of material two holes in it ( heater+thermometer to go into).
2)Measure mass block, wrap insulating layer reduce energy transferred. thermometer +heater.
3) Measure initial temperature block, stop watch.
4)block heats up, take readings temperature + current,every minute for 5 minutes.
6) calculate how much energy, transferred heater each temperature reading
7) plot a graph
8)repeat experiment different materials specific heat capacities
1)Conservation of Energy Principle, what happens to energy (2)?
2)Where does energy go and what happens?
3)what is wasted energy called?
1) energy is always conserved: transferred usefully to stored or dissipated,but can never be created or destroyed.
2) energy is transferred between stores. Some energy always dissipated when an energy transfer happens.
3) Dissipated energy is sometimes called ‘wasted energy’=not useful
Describe energy transfers for closed systems when a cold spoon in dropped into a flask of soup?
.cold spoon is dropped insulated flask of hot soup, sealed. flask perfect thermal insulator spoon+soup=closed system.
.Energy transferred thermal energy store soup to useless thermal energy store spoon (soup to cool down)
.Energy transfers have occurred within system, no energy has left the system (net change in energy is zero)
1)What is Power and units?
2)what does one watt= ? Joule per second?
.Power is the rate of energy transfer/doing work. measured in watts. One watt = 1 joule per second.
.power (w)= energy transferred(J)/time(s) .power(W)= work done(J)/Time (S)
How do solids heat up by conduction? 3
1)energy is shared across kinetic energy stores of the particles in the object.
2) particles part of the object heated vibrate more collide with each other. Collisions=energy to be transferred between particles’ kinetic energy stores.
3)continues throughout object until the energy is transferred to the other side the object. Transferred=thermal energy store surroundings
