energy

Question 1

Name 4 energy stores

Answer 1

thermal
kinetic
gravitational potential
elastic potential 
chemical
magnetic
electrostatic 
nuclear

Question 2

what is a system

Answer 2

a single object or group of objects that you are interested in

Question 3

when a system changed

Answer 3

energy is transferred

Question 4

what is work done

Answer 4

energy transferred

Question 5

describe the energy transfer when wind hits a windmill

Answer 5

the energy transfers from the gravitational potential energy store of the wind to the kinetic energy store of the windmill

Question 6

what is the equation for kinetic energy

Answer 6

ek=1/2mv^2

Question 7

what is the equation for gravitational potential energy

Answer 7

ep=mgh

Question 8

when something falls

Answer 8

energy from its gravitational energy store is transferred to its kinetic energy store

Question 9

what is the equation for elastic potential energy

Answer 9

ew=1/2ke^2

Question 10

more energy needs to be transferred to the … energy store of some materials to … their temperature

Answer 10

thermal energy store, increase

Question 11

what is the equation for specific heat capacity

Answer 11

/\E=mc/\ø (mass x specific heat capacity x temperature change

Question 12

energy can never be … nor …

Answer 12

created , destroyed

Question 13

dissipated energy can also be called

Answer 13

wasted energy

Question 14

lubrication reduces

Answer 14

frictional forces

Question 15

heating can occur by two methods, these are:

Answer 15

convection and conduction

Question 16

an equation linking power,energy transferred and time is:

Answer 16

p=e/t

Question 17

an equation linking: power, work done and time is:

Answer 17

p=w/t

Question 18

insulation reduces the rate of what transfer and how?

Answer 18

energy transfer
and
heating

Question 19

useful devices are useful because

Answer 19

they can transfer energy from one store to another

Question 20

the equation linking useful energy transfer, efficiency and total input energy transfer is

Answer 20

efficiency= useful output energy/total input energy

Question 21

electric heaters are usually …% effective

Answer 21

100

Question 22

name some non renewable recourses

Answer 22

coal
oil
natural gas

Question 23

name renewable energy stores

Answer 23

the sun 
wind
waves
hydroelectricity 
bio-fuel
tides
geothermal

Question 24

non renewable recourses are…

Answer 24

reliable

Question 25

one disadvantage of non renewable recourses

Answer 25

releases harmful gases weakening the o zone