Conservation Of Energy

Question 1

Kinetic

Answer 1

Anything moving has energy in its kinetic energy store

Question 2

Thermal

Answer 2

Any object- the hotter it is the more energy it has in this store

Question 3

Chemical

Answer 3

Anything that can release energy by a chemical reaction (food, muscles, fuels)

Question 4

Gravitational Potential

Answer 4

Anything inside a gravitational field (something that can fall) (roller coster at the top, aero plane)

Question 5

Elastic

Answer 5

Something that can be stretched twisted squashed (rubber, springs)

Question 6

Magnetic

Answer 6

Two magnets that attract or repel each other

Like poles unlike poles

Question 7

Electrostatic

Answer 7

Two charges that attract or repel each other

Question 8

Nuclear

Answer 8

Atomic nuclei release energy from this store in nuclear reactions

Question 9

Mechanically

Answer 9

An object moving due to a force acting on it (push pull)

Question 10

Electrically

Answer 10

A charge moving due to a potential difference (charges moving around a circuit)

Question 11

By heating

Answer 11

Energy transfer from a hotter object to a colder object.

Question 12

By radiation

Answer 12

Energy transfer by waves (light or sound waves) (energy from the sun reaching the Earth

Question 13

Principal of conservation of energy

Answer 13

Energy can’t be created or destroyed it changes from one store to another.

Question 14

Total energy input=

Answer 14

Useful energy output + wasted energy

Question 15

Efficiency=

Answer 15

Useful energy output/ total energy output x 100

Question 16

Conduction

Answer 16

Thermal conduction is the process where vibrating particles transfer energy from their kinetic energy store to the kinetic energy store of neighbouring particles.
(Experiment Bunsen burner metal bar attached with breads)

Question 17

Convection

Answer 17

Convection occurs when the more energetic particles move from the hotter region as they are less dense to the colder regions and become more dense- and transfer energy as they do so.

Question 18

Convection current is

Answer 18

When you heat the water or air particles and they become less dense meaning that they are going to rise and in the process collide with other more dense colder particles and transfer their energy making them more dense and cooler and as a result the dense particles will sink again. This process will be repeated constantly.

Question 19

Radiation

Answer 19

Transfer of energy through waves. Eg. Sound or light waves

Question 20

To reduce conduction use

Answer 20

Materials with low thermal conductivity such as plastic or wood

Question 21

To reduce convection

Answer 21

Stop the fluid from moving and use a insulator (cloths or blankets) to reduce the energy

Question 22

To reduce radiation

Answer 22

The object should be designed with a surface that is a poor emitter such as white or shiny.
If it’s black or it’s not going to reduce the radiation, as black is a good emitter and white a good reflector.

Question 23

Work done =

Answer 23

Force x distance moved

Question 24

Power=

Answer 24

Work done / Time taken

Question 25

Energy in kinetic energy store=

Answer 25

1/2 x mass x speed2

Question 26

Gravitational potential energy=

Answer 26

Mass x height x gravitational field strength