T1 Energy stores

Question 1

State the law of conservation of energy.

Answer 1

energy cannot be created or destroyed, but only changed from one form into another

Question 2

State the 8 energy stores you need to know

Answer 2

Thermal energy, chemical energy, kinetic energy, magnetic energy, gravitational potential, electrostatic, elastic potential, nuclear energy

Question 3

What 4 ways can energy be transferred?

Answer 3

1) Mechanically (by a force doing work)
2) Electrically (work done by a moving charges)
3) Heating
4) Radiation (sound, light)

Question 4

What happens when a system changes?

Answer 4

Energy is transferred

Question 5

What is a system?

Answer 5

A fancy word for a single object (e.g. the air in a piston) or a group of objects (e.g. two colliding vehicles) that you’re interested in.

Question 6

What is internal energy?

Answer 6

The energy stored in a system by the particles.

Question 7

What is a closed system?

Answer 7

A system where neither matter nor energy can enter or leave.

Question 8

What is the net change in the total energy of a closed system?

Answer 8

always zero 0000

Question 9

Take the example of boiling water in a kettle. What is the system?

Answer 9

The water

Question 10

Take the example of boiling water in a kettle. How is energy transferred to the water?

Answer 10

By heating

Question 11

What is work done the same as?

Answer 11

Energy transferred

Question 12

Work can be done in what 2 ways?

Answer 12

1) When current flows (work is done against the resistance in a circuit)
2) By a force moving an object

Question 13

Energy lost from the g.p.e. store =

Answer 13

energy gained in the kinetic energy store

Question 14

Any moving thing has what?

Answer 14

Energy in its kinetic energy store

Question 15

When an object speeds up what happens?

Answer 15

Energy is transferred to the kinetic energy store

Question 16

When an object slows down what happens?

Answer 16

Energy is transferred away from the kinetic energy store

Question 17

What does the energy in the kinetic energy store depend on?

Answer 17

The objects mass and speed

Question 18

What is the formula linking kinetic energy, mass and speed?

Answer 18

Kinetic energy = 1/2 x mass x speed squared

Question 19

Unit for kinetic energy (E)

Answer 19

J Joules

Question 20

Unit for mass (M)

Answer 20

kg kilograms

Question 21

Unit for speed (V)

Answer 21

(m/s)squared

Question 22

Where do raised objects store energy?

Answer 22

Gravitational potential energy stores

Question 23

Lifting an object in a gravitational field requires work. What does this cause?

Answer 23

a transfer of energy to the g.p.e. store of the raised object

Question 24

What does the amount of energy in a g.p.e. store depend on?

Answer 24

The objects mass, its height and the strength of the gravitational field.

Question 25

What equation can you use for g.p.e.?

Answer 25

gravitational potential energy = mass x gravitational filed strength x height

Question 26

Unit for g.p.e.

Answer 26

J Joules

Question 27

Unit for mass

Answer 27

kg

Question 28

Unit for gravitational field strength

Answer 28

N/Kg

Question 29

Unit for height

Answer 29

m meters

Question 30

Stretching somethings transfers energy where?

Answer 30

To the objects elastic potential energy stores.

Question 31

Equation for elastic potential energy

Answer 31

elastic potential energy = 1/2 x spring constant x extension^squared

Question 32

Unit for elastic potential energy

Answer 32

J joules

Question 33

Unit for spring constant

Answer 33

N/m

Question 34

Unit for extension

Answer 34

m

Question 35

specific heat capacity is what

Answer 35

It is the energy needed to increase the temperature of 1 kg of the substance by 1°C

Question 36

the measure of how much energy a substance can store is called

Answer 36

specific heat capacity

Question 37

Equation for specific heat capacity =

Answer 37

change in thermal energy = mass x specific heat capacity x temperature change

Question 38

Unit for change in thermal energy

Answer 38

J Joules

Question 39

Unit for mass

Answer 39

kg

Question 40

Unit for specific heat capacity

Answer 40

J/kg°C

Question 41

Unit for temperature change

Answer 41

°C

Question 42

What happens to ‘waste energy’?

Answer 42

It is dissipated into the surroundings

Question 43

What is power?

Answer 43

The rate or energy transfer or rate of doing work

Question 44

What is power measured in?

Answer 44

Watts, W

Question 45

What is one watt equal to?

Answer 45

1 joule of energy transferred per second

Question 46

2 power equations

Answer 46

1) power = energy / time

2) power = work done / time

Question 47

What is conduction?

Answer 47

The process where vibrating particles transfer energy to neighbouring particles.

Question 48

Conduction

1) Energy transferred to an object by _____ is transferred to the _____ _____ of the object. This energy is shared across the _____ energy _____ of the ______ in the object.
2) The _____ in the part of the object being heated _____ more and _____ with each other. These ______ cause energy to be transferred between particles’ _____ energy stores. This is ______.
3) This process ______ ______ the object until the energy is transferred to the _____ ___ of the object. It’s then usually transferred to the _____ energy store of the ______.
4) _______ _______ is a measure of how quickly energy is transferred through a material in this way. Materials with _____ ______ _______ transfer energy between their particles _____.

Answer 48

1) Energy transferred to an object by heating is transferred to the thermal store of the object. This energy is shared across the kinetic energy stores of the particles in the object.
2) The particles in the part of the object being heated vibrate more and collide with each other. These collisions cause energy to be transferred between particles’ kinetic energy stores. This is conduction.
3) This process continues throughout the object until the energy is transferred to the other side of the object. It’s then usually transferred to the energy store of the surroundings.
4) Thermal conductivity is a measure of how quickly energy is transferred through a material in this way. Materials with high thermal conductivity transfer energy between their particles quickly.

Question 49

What is convection? ( hot air rises )

Answer 49

Convection is where energetic particles move away from hotter to cooler regions.

Question 50

Convection

1) ____ can happen in _____ and _____. Energy is transferred __ _____ to the _____ ____ of the liquid or gas. As with conduction, this energy is shared across the ____ energy stored of the gas or liquid’s particles.
2) Unlike in solids, the particles in liquids and gases are ___ __ ___. When you heat a region of a gas or liquid, the particles ___ ____ and the space between the individual particles ______. This causes the _____ of the region being heated to ______.
3) Because liquids and gases can ___, the warmer and less dense region will ___ above _____, ____ regions. If there is a _____ heat source, a _______ _____ can be created.

Answer 50

1) Convection can happen in gases and liquids. Energy is transferred by heating to the thermal store of the liquid or gas. As with conduction, this energy is shared across the kinetic energy stored of the gas or liquid’s particles.
2) Unlike in solids, the particles in liquids and gases are able to move. When you heat a region of a gs or liquid, the particles move faster and the space between the individual particles increases. This causes the density of the region being heated to decrease.
3) Because liquids and gases can flow, the warmer and less dense region will rise above denser, cooler regions. If there is a constant heat source, a convection current can be created.

Question 51

What objects can create convection currents?

Answer 51

radiators