Energy stores and transfers-PAPER 1

Question 1

What is the efficiency equation?

Answer 1

EFFCIENCY=useful output energy transfer/total input energy transfer
EFFCIENCY=useful power output/total power input

Question 2

What is internal energy?

Answer 2

internal energy is the total kinetic energy and potential energy of all the particles that make up a system

Question 3

What is specific heat capacity?

Answer 3

the specific heat capacity of a substance is the amount of energy required to raise the temp of one kilogram of the substance by one degree Celsius

Question 4

What is the law of conservation of energy?

Answer 4

energy can be stored or dissipated to its surroundings but it cannot be made or destroyed

Question 5

What is the difference between renewable and non-renewable energy?

Answer 5

renewable-can be replenished

non renewable-energy resources will eventually run out

Question 6

What is Kinetic energy?

Answer 6

ke is energy stored in moving objects, if its not moving there’s no ke

Question 7

What is elastic potential energy?

Answer 7

when stretching springs we use force to change its length it then stores elastic potential energy
Joules (J)

Question 8

What is GPE?

Answer 8

GPE is the energy stored in an object due to its position above the earths surface
GPE=M(kg) x G x H(m)

Question 9

What is work done?

Answer 9

WD= F x D(m)

Question 10

How do you start the practical for insulating ?

Answer 10

• Take 4 copper calorimeters and wrap each one in different insulators use a rubber band to secure the insulators
• fill each tube with warm water and measure the start temp

Question 11

How does doing work on a system change the energy store?

Answer 11

• heating changes the energy stored in a system
• When the temp increases it will either increase the temp of change the state
• If the temp increases it depends on;
• mass of the substance heated
• the substance
• the energy input

Question 12

What is the equation of change in thermal energy?

Answer 12

CHANGE IN THERMAL ENERGY=MASS X SPECIFIC HEAT CAPACITY X TEMPREATURE CHANGE

Question 13

what is the equation for mass in relations with specific heat capacity?

Answer 13

MASS=CHANGE IN THERMAL ENERGY/SPECIFIC HEAT CAPCITY x TEMPREATURE CHANGE

Question 14

What happens in a closed system?

Answer 14

in a closed system total energy never changes but it can be transferred

Question 15

How is wasted energy transfers caused and how do we stop it?

Answer 15

wasted energy is caused by unwanted energy transfers .These unwanted energy transfers can be reduced by lubrication and tightening any loose parts

Question 16

What is power?

Answer 16

power is the rate of which energy is transferred or work is done
Power(W)= energy transferred /time
Power=work done/time

Question 17

What are the variables for the practical?

Answer 17

• independent-type of insulation
• dependent-temp
• control-temperature is measured, volume of water, thickness of insulating material

Question 18

What are the hazards and errors?

Answer 18

*hot water is a hazard it may cause a burn
ERORRS
*cooling curve should be a smooth curve if the temperature goes up or down keep it as an anomaly

Question 19

What do you do after filling the tubes with warm water?

Answer 19

• start the stopwatch and record the temp every min for 10 min
• plot the results for time against temp

Question 20

What is the useful and wasted energy in a radio?

Answer 20

useful-sound

wasted-heat (infrared radiation)

Question 21

What is the useful and wasted energy in a tumble dryer?

Answer 21

useful-thermal energy

wasted-sound

Question 22

What is the equation for elastic potential energy?

Answer 22

Ee=0.5 x K x E2(m)

elastic potential energy=0.5 x spring constant x extension2

Question 23

What is the equation for kinetic energy?

Answer 23

KE=0.5 x M x V2

M=KE/0.5 x V2