energy

Question 1

what is internal energy

Answer 1

the total energy stored by particles making a substance or system

Question 2

what is specific heat capacity

Answer 2

amount of energy needed to raise the temperature of 1kg of a substance by 1 degree celcius

Question 3

specific heat capacity of water

Answer 3

4200j/kg degrees celcius

Question 4

what also happens to materials that need to gain lots of energy in their thermal energy stores to warm up

Answer 4

they transfer loads of energy when cooling down as they store alot of energy

Question 5

what equiptment is required in a specific heat capacity practical

Answer 5

-power supply
-heater
-ammeter
-thermometer
-block of material
-insulation material

Question 6

what energy store is movement

Answer 6

kinetic store

Question 7

energy is transferred to a kinetic store when..

Answer 7

an object speeds up

Question 8

energy is transferred away from a kinetic store when

Answer 8

object slows down

Question 9

what energy store is a raised object

Answer 9

gravitational potential energy

Question 10

the higher an object is lifted..

Answer 10

the more energy is transferred to gravitational potential energy

Question 11

falling object

Answer 11

transfers energy from gravitational potential energy to kinetic energy

Question 12

stretching transfers to..

Answer 12

elastic potential energy

Question 13

definition of energy

Answer 13

the ability to do work

Question 14

can energy be created or distroyed

Answer 14

no it can only be tranferred between different objects

Question 15

open system

Answer 15

system where mass can be lost or gained from the environment

Question 16

closed system

Answer 16

a system where it does not allow transfer of mass in or out of the system

Question 17

definition of work done

Answer 17

amount of force applied for an object to move

Question 18

two types of work done

Answer 18

mechanical and electrical

Question 19

mechanical work done

Answer 19

force to move an object

Question 20

example of mechanical work done

Answer 20

kicking a ball
(movemnt of feet is a chemical energy which transfers to the ball which is kinetic energy)

Question 21

electrical work done

Answer 21

when current flows energy required to overcome resistance in a wire

Question 22

what reduces frictional forces

Answer 22

lubricants eg oil on a pedal bike to stop the heavy friction

Question 23

what happens when energy is trasnferred between stores

Answer 23

some energy is dissipated “wasted energy” eg- phone heating up when using it does not help the phone to work

Question 24

definition of power

Answer 24

rate of doing work

Question 25

whats power measured in

Answer 25

watts

Question 26

energy transfer for a closed system

Answer 26

energy can be transferred between energy stores within a closed system eg a spoon in a hot flask of soup

Question 27

how is thermal conductivity measured

Answer 27

how quickly energy is transferred through a material

Question 28

what does it mean by a material having a "high thermal conductivity"

Answer 28

the transfer of energy between their particles is at a faster rate

Question 29

what is the job of insulation

Answer 29

reduces the rate of energy transfer by heating

Question 30

4 examples of insulation

Answer 30

cavity walls,loft insulation,double glazed windows,draught excludes

Question 31

definition of convection

Answer 31

heat is transferred through gas and liquid

Question 32

definition of conduction

Answer 32

heat is lost through a solid

Question 33

name a pro and a con for using cavity walls

Answer 33

having the air in the middle stops conduction however the air can alow convection to happen.

Question 34

what will make cavity walls more efficient

Answer 34

putting insulating foam in the middle of both walls

Question 35

problem with friction

Answer 35

it reduces efficiency of energy transfer-unwanted energy such as heat

Question 36

definition of efficiency

Answer 36

using less energy to perform the same task

Question 37

the less energy that is wasted..

Answer 37

the more efficient the device is said to be

Question 38

how to improve effieciency

Answer 38

insulating objects,lubricants or making them more streamlined