Energy (physics)

Question 1

Name the 5 energy stores…

Answer 1

Thermal
Kinetic
Chemical
Elastic potential 
Gravitational potential

Question 2

What is the conservation of energy law…

Answer 2

ENERGY CANT BE CREATED OR DESTROYED

Question 3

Energy I measured in

Answer 3

Joules

Question 4

Explain what happens when energy ‘dissipates’…

Answer 4

Some energy dissipates into the surroundings (it spread out into the surroundings). Normally this is by friction heating up the surroundings or sound/light waves.

Question 5

Thermal energy…

Answer 5

• All objects have it

- it is the energy a substance has due to its kinetic energy of its particles

Question 6

Elastic potential…

Answer 6

• When objects stretch they have the potential to return to their original shape.
• Likewise when you squash a material

Question 7

Kinetic energy….

Answer 7

Energy stored be a an object is moving

Question 8

Gravitational potential energy…

Answer 8

Energy an object passes due to its position in a gravitational field

Question 9

Work =

Answer 9

Work= force x distance

Question 10

Weight =

Answer 10

Weight = mass x gravitational field strength (kg & N/kg)

Question 11

Kinetic energy =

Answer 11

Kinetic energy (J) x mass x 1/2 x velocity^2

Question 12

Power=

Answer 12

Power = Energy/time

Question 13

How do you calculate efficiency?

Answer 13

Efficiency = (useful power output/total power input ) x100

Question 14

Work is …

Answer 14

Moving about a force

Question 15

Chemical potential energy

Answer 15

• Chemical energy is a type of stored energy that is released by a chemical reaction
• feul food and batteries contain chemical potential

Question 16

What is specific heat capacity?

Answer 16

Specific heat capacity is the amount of energy required to raise the temperature of 1 kg of a substance by 1°

Question 17

what does friction have to do with energy?

Answer 17

Friction causes energy to be transferred to thermal energy. The store is a thermal energy and less useful, the energy has been dissipated/wasted.

Question 18

Specific heat capacity (this equation is given in the exam)

Answer 18

Energy transferred = mass(kg) x SHC (J/kg°C) x temperature change (°C )

Question 19

Conduction is ….

Answer 19

Energy transferred three collisions between neighbouring vibrating particles, this only takes place in solids.

Question 20

Convection is …

Answer 20

Energy transferred from rising regions of a fluid. Takes place in liquids and gases

Question 21

Radiation is…

Answer 21

Energy transferred by electromagnetic radiation. Takes place in liquids and gases -for example energy reaching us from the Sun

Question 22

Evaporation is…

Answer 22

Energy transferred away from the surface of a liquid by scraping high energy particles. And example of this is cooling of a hot drink.

Question 23

Condensation is….

Answer 23

Energy transferred to a solid by a gas forming a liquid on the service – for example the missing of mirrors and windows.

Question 24

What is meant by a renewable energy source?

Answer 24

An energy source which is replenished by natural processes as it’s being used

Question 25

Name three examples of renewable energy sources:

Answer 25

• solar
• hydroelectric and tidal
• wind (wind turbines)
• geothermal
• biofuels

Question 26

What is specific LATENT heat?

Answer 26

Is the amount of energy needed to change 1 kg of the substance from one state to another without changing its temperature

Question 27

What is the equation for specific latent heat?

Answer 27

Energy (j) = mass (kg) x latent heat (j/kg)