physics topic 1

Question 1

what is energy’s unit of measure?

Answer 1

Joules / J

Question 2

Chemical energy

Answer 2

Energy that can be released in a chemical reaction, eg. burning , it can be stored

Question 3

Elastic energy

Answer 3

Energy in a deformed (stretched) elastic object e.g elastic band, it can be stored

Question 4

Light energy

Answer 4

Energy given off by a luminous object eg. light bulb, it can be transferred

Question 5

Thermal energy

Answer 5

Heat energy; energy that can raise the temperature of an object e.g fire, it can be stored

Question 6

Electrical energy

Answer 6

A means of transferring energy with a flow of electrons (electrical current) eg. charger, it can be transferred

Question 7

Gravitational potential energy

Answer 7

Energy stored by an object of mass when it is lifted to a certain height in a gravitational field. e.g. flying bird, it can be stored

Question 8

Kinetic energy

Answer 8

Energy stored in a moving object eg. car, it can be stored

Question 9

sound energy

Answer 9

Energy transferred by vibrations through a medium, eg. speakers, it can be transferred

Question 10

TRUE OR FALSE, energy cannot be created, destroyed

Answer 10

TRUE —> it can be recycled to form another (it is therefore transferred)

Question 11

Gravitational potential equation

Answer 11

Ep = m x g x h
Gravitational potential energy = Mass (kg) x Gravitational field strength (N/kg) x Height (m)

Question 12

make mass subject of gravitational potential equation

Answer 12

m = Ep ÷ gxh

Question 13

make gravitational field strength subject in gravitational potential equation

Answer 13

Ep÷mxh

Question 14

Make mass subject of kinetic energy formula

Answer 14

M= Ek÷ 1/2 x v²

Question 14

make height subject in gravitational potential equation

Answer 14

Ep÷mxg

Question 14

4 part method to equations:

Answer 14

1) Write equation you are using and identify numbers
2) Rearrange equation if it is necessary
3) Substitute values
4) Solve

Question 15

Kinetic energy equation

Answer 15

Ek= 1/2 x m x v²
Kinetic energy= 1/2 x mass (kg) x velocity (or speed) (m/s)

Question 16

Make velocity subject of kinetic energy formula

Answer 16

V= √Ek÷ 1/2 x m

Question 17

Doubling the mass _____ the kinetic energy.
Doubling the speed ______ the kinetic energy

Answer 17

1 Mass
2 x4
Doubling the speed increases the kinetic energy more than the mass.

Question 18

Elastic potential energy formula

Answer 18

Ee= 1/2 x k x e²
Elastic potential energy = 1/2 x spring constant (n/m) x extension (m) –> the amount the object has been extended, not length

Question 19

What is an elastic:

Answer 19

An elastic object is something that can be deformed by a force but will be able to return to its original form. While the elastic object is deformed (extended, squashed), it stores elastic potential energy.

Question 20

Make spring constant the subject in elastic potential equation

Answer 20

Spring constant / k = Ee ÷ 1/2 x e²

Question 21

Make extension the subject in elastic potential equation

Answer 21

E=√ Ee÷ 1/2 x k

Question 22

What are the 5 energy stores?

Answer 22

Chemical, thermal, kinetic, gravitational potential energy, elastic potential energy.

Question 23

What are the 4 energy transfers?

Answer 23

Mechanically, hearing, radiation, electrically

Question 24

CONSERVATION OF ENERGY:

Answer 24

Energy cannot be created or destroyed, instead it is transferred from one energy store to another.

Question 25

Closed system:

Answer 25

No energy is allowed in/out

Question 26

Open system:

Answer 26

Energy can be transferred out/in from surroundings

Question 27

DEFINE Efficiency

Answer 27

The percentage of useful energy compared to the total energy.

Question 28

Efficiency formula:

Answer 28

useful energy (J) ÷ total energy in (J) x100 percent

Question 29

Unit of power

Answer 29

Watts Kilowatts (1000) Megawatts (1,000,000)

Question 30

Make useful output the subject of the efficiency formula

Answer 30

Efficiency ÷ Total energy output (J)

Question 31

Define system

Answer 31

Group

Question 32

Wasted energy:

Answer 32

When energy goes towards things that aren't necessary

Question 33

What is a control variable?

Answer 33

The variable you don't change

Question 34

What is an independent variable?

Answer 34

The thing you change/ vary in an investigation

Question 35

What is a dependant variable?

Answer 35

The thing you measure in an investigation

Question 36

State the accepted value of 'g' to 2 significant figures

Answer 36

9.8

Question 37

Power equation

Answer 37

power = Energy transferred ÷ Time

Question 38

Energy equation

Answer 38

Energy transferred = power x time (S)

Question 39

Time equation

Answer 39

Energy transferred ÷ power

Question 40

what is a conductor in physics?

Answer 40

Materials or substances that allow electricity to pass through them easily eg. metals. They are good conductors for heat

Question 41

What is a insulator in physics?

Answer 41

Materials or substances that do not allow electric current to pass through them. They have high resistance and are called insulators as they are poor conductors.

Question 42

What are renewable resources?

Answer 42

Renewable resources that replenish as they are being used.

Question 43

What are non-renewable resources

Answer 43

non-renewable resources that will run out due to a limited supply