energy and energy equations - Physics

Question 1

give the equation to weight and it’s units

Answer 1

Weight = mass x gravity
N = Kg x N/kg

Question 2

give the equation to gravitational potential energy and its units

Answer 2

Gravitational potential energy = mass x gravity x height
J= Kg x N/Kg x m

Question 3

give the equation to elastic energy and give the units

Answer 3

Ee = 0.5 x spring constant x extension^2
J = 1/2 x N/m x m

Question 4

give the equation to kinetic energy and give the units

Answer 4

Ek = 1/2 x mass x velocity/speed^2
J = 1/2 x kg x m/s

Question 5

what is the order of a coal power station

Answer 5

furnace, boiler, turbine, generator

Question 6

give the equation to efficiency and it’s units

Answer 6

useful output energy
efficiency = ——————————
total input energy
J
efficiency = —
J

Question 7

give the ways energy is transferred

Answer 7

light and waves, electrical current, thermally, by a force

Question 8

what gas is also released in the burning of coal?

Answer 8

SO2

Question 9

give all the of the energy stores

Answer 9

kinetic, elastic, chemical, gravitational, thermal, nuclear, electric magnetic

Question 10

what is the main source of energy used by the uk?

Answer 10

biomass or wood chips

Question 11

give the equation to work done and it’s units

Answer 11

Work done = Force x distance
Joules = Newtons x meters

Question 12

what is biofuel

Answer 12

fuels that are made by harvesting plants such as trees

Question 13

give the equation to power and it’s units

Answer 13

. Energy
P = ———
time
J
w = —
s

Question 14

what is specific heat capacit?

Answer 14

the amount of energy needed to raise the temperature of a mass of a material by 1°C

Question 15

give the equation NEEDED for specific heat capacity and its units

Answer 15

change in thermal energy (J) = mass (kg) x specific heat capacity (J/Kg°C) x change in temperature (°C)

Question 16

what does it mean when a material is a ‘conductor’?

Answer 16

when a a material has a high thermal conductivity such as iron or stainless steel

Question 17

what does it mean when a material is a ‘insulator’?

Answer 17

when a material has a low thermal conductivity such as wood or plastic

Question 18

what is loft insulation and how does it work?

Answer 18

the glass fibres are a poor thermal conductor, as well as the air within it, stopping the circulation of air, preventing heat

Question 19

how does cavity wall insulation work?

Answer 19

the space between the 2 brick walls is filled with an insulator. This could be foam or polystyrene balls

Question 20

give some examples of every day insulators

Answer 20

• loft insulators
• cavity wall insulators
• double glazed windows