energy

Question 1

what happens when a system changes

Answer 1

the way energy stored also changes

Question 2

unit for energy

Answer 2

joules

Question 3

units for mass

Answer 3

kg

Question 4

units for speed

Answer 4

meters per second

Question 5

units for spring constant

Answer 5

newtons per metre

Question 6

units for extention

Answer 6

meters

Question 7

define power

Answer 7

the rate at which energy is transferred or the rate at which work is done

Question 8

units for time

Answer 8

seconds

Question 9

what is one watt = to

Answer 9

one joule per second

Question 10

what is one joule per second = to

Answer 10

one watt

Question 11

law of conservation of energy

Answer 11

energy cannot be created or destroyed only transferred , stored , or dissipated

Question 12

2 ways to reduce unwanted energy tansfers

Answer 12

thermal insulation and lubrication

Question 13

what happens to thermal conductivity as conduction increases

Answer 13

the rate of energy transfer by conductivity to the material increases

Question 14

2 factors that affect the rate of cooling of a building

Answer 14

thickness and thermal condictivity of its walls

Question 15

give an example of how lubrication reduces unwanted energy transfers

Answer 15

• lubrication ( i.e oil in a motor)
• reduces friction
• so less thermal energy is lost

Question 16

give an example how thermal insulation reduces unwanted energy transfers

Answer 16

• thermal insulation ( i.e double glazing)
• less useful thermal energy lost

Question 17

how is efficiency increased

Answer 17

• reducing waste output
• recycling waste output

Question 18

system

Answer 18

object or a group of objects

Question 19

kinetic energy formula

Answer 19

0.5 x mass x extension*2

Question 20

what is mass measured in

Answer 20

kg

Question 21

what is speed / velocity measured in

Answer 21

m/s

Question 22

elastic potential formula

Answer 22

0.5 x spring constant x extension*2

Question 23

what is spring constant measured in

Answer 23

n/m - newtons per metre

Question 24

what is extension measured in

Answer 24

m

Question 25

gravitational potential formula

Answer 25

mass x gravitational field strength (9.81) x height

Question 26

what is gravitational field strength measured in

Answer 26

n/kg

Question 27

what is height measured in

Answer 27

metres

Question 28

change in thermal energy

Answer 28

mass x specific heat capacity x temperature change

Question 29

what is specific heat capacity measured in

Answer 29

j/kg*degrees celsius

Question 30

summarise shc practical

Answer 30

• heating up a block of copper using an electric heater
• measuring : mass ,work done by heater and temperature
• plot graph of temperature against work done
• gradient and mass will determine shc

Question 31

how do you set up shc practical (steps 1-4)

Answer 31

• 1 measure and record the mass of the copper block (with two holes in it)
• 2 place the heater in the larger hole
• 3 connect the ammeter , power pack and heater in series
• 4 connect the voltmeter across the power pack

Question 32

how do you carry out the shc practical (steps 4-10)

Answer 32

• 5 use the pippette to put water in the hole
• 6 put the thermometer in the hole
• 7 put on the power pack at 12 volts
• 8 record ammeter and voltmeter readings (these should remain the same)
• 9 measure the temperature and start the stop clock
• 10 record the temperature every minute for 10 minutes

Question 33

specific heat capacity hypothesis

Answer 33

metal blocks with the same mass but different volumes have a bigger specific heat capacity

Question 34

sch practical equipment (9)

Answer 34

• 1kg copper iron and aluminium blocks with two holes
• thermometer
• pippette
• 12v power supply
• heater
• insulation
• ammeter
• voltmeter
• stop clock

Question 35

how much equipment is needed for specific heat capacity pactical

Answer 35

9