Conservation And Dissapation Of Energy

Question 1

What is Kinetic Energy?

Answer 1

The energy stored by objects that are moving.

Question 2

What is Gravitational Potential Energy?

Answer 2

The energy stored in objects raised above the ground.

Question 3

What is Chemical Energy?

Answer 3

The energy stored in fuels, food, and batteries.

Question 4

What is Thermal Energy?

Answer 4

The energy stored by hot objects.

Question 5

What is Elastic Potential Energy?

Answer 5

The energy stored by stretched or squashed objects.

Question 6

What is a system?

Answer 6

A system is an object or group of objects.

Question 7

What is the conservation of energy?

Answer 7

In a closed system, energy cannot be created or destroyed. The total energy is constant.

Question 8

What happens to energy in system changes?

Answer 8

Energy is dissipated so that it is stored in less useful ways (wasted energy).

Question 9

How can unwanted energy transfers be reduced?

Answer 9

Using lubrication (to reduce friction) or insulation (to reduce the rate of thermal energy transfer).

Question 10

What is power?

Answer 10

Power is defined as the rate at which energy is transferred, or the rate at which work is done.

Question 11

How is power measured?

Answer 11

An energy transfer of 1 joule per second is equal to a power of 1 watt.

Question 12

How does motor power affect lifting time?

Answer 12

A higher power motor will lift the mass in a shorter time, while a lower power motor will lift it in a longer time.

Question 13

How is efficiency calculated?

Answer 13

Efficiency = Useful Energy Output or Useful Power Output / Total Energy Input or Total Power Input.

Question 14

What is the unit of efficiency?

Answer 14

Efficiency has no unit.

Question 15

What is the equation for work done?

Answer 15

Work done = Force x Distance

W = F x s

Question 16

What is the equation for Kinetic Energy?

Answer 16

Kinetic Energy = 1/2 x mass x speed²

E_k = 1/2 x m x v²

Question 17

What is the equation for Gravitational Potential Energy?

Answer 17

Gravitational Potential Energy = mass x gravitational field strength x height

E_p = m x g x h

Question 18

What is the equation for Power?

Answer 18

Power = Energy / Time

P = E / t

Question 19

What is the equation for Elastic Energy?

Answer 19

Elastic Energy = 1/2 x spring constant x extension²

E_e = 1/2 x k x x²

Question 20

What is energy transfer by conduction?

Answer 20

Energy transfer by conduction is the process where energy moves through a material due to a temperature difference.

Question 21

How does thermal conductivity affect energy transfer?

Answer 21

The higher the thermal conductivity of a material, the higher the rate of energy transfer by conduction across the material.

Question 22

What factors affect the rate of energy transfer through insulation?

Answer 22

The rate of energy transfer depends on the temperature difference across the material, the thickness of the material, and the thermal conductivity of the material.

Question 23

How does temperature difference affect energy transfer?

Answer 23

The larger the temperature difference across the material, the higher the rate of energy transfer by conduction.

Question 24

How does thickness affect energy transfer?

Answer 24

The thicker the material, the lower the rate of energy transfer by conduction.

Question 25

What are some ways to reduce energy loss in homes?

Answer 25

Ways to reduce energy loss include loft insulation, energy efficient boilers, cavity wall insulation, installing solar panels, double glazing, and using draft excluders.

Question 26

What is specific heat capacity?

Answer 26

Specific heat capacity is the amount of energy required to raise the temperature of one kilogram of a substance by one degree Celsius.

Question 27

What is the equation for change in thermal energy?

Answer 27

Change in thermal energy = mass x specific heat capacity x change in temperature. ## Footnote AE = m x c x Δθ

Question 28

What are the units for change in energy?

Answer 28

Change in energy is measured in Joules (J), mass in kilograms (kg), specific heat capacity in Joules per kilogram per degree Celsius (J/(kg°C)), and change in temperature in degrees Celsius (°C).

Question 29

How do you rearrange the specific heat capacity equation?

Answer 29

c = ΔE / (m x Δθ)

Question 30

What is the specific heat capacity of a material if 4000J changes the temperature of 2kg by 3°C?

Answer 30

The specific heat capacity is 667 J/(kg°C). ## Footnote Calculation: c = 4000 / (2 x 3)

Question 31

What is the aim of the specific heat capacity practical?

Answer 31

The aim is to determine the specific heat capacity of various materials.

Question 32

What is the independent variable in the specific heat capacity practical?

Answer 32

The independent variable is the material being tested.

Question 33

What equipment is needed for the specific heat capacity practical?

Answer 33

Equipment includes a Joulemeter, immersion heater, metal block, and thermometer.

Question 34

What is the method for determining specific heat capacity?

Answer 34

1. Measure the mass of the block. 2. Measure the starting temperature. 3. Increase the temperature using an immersion heater. 4. Measure energy input. 5. Record end temperature and calculate temperature difference. 6. Use the equation to find specific heat capacity.

Question 35

What improvements can be made in the specific heat capacity practical?

Answer 35

Wrap the block in insulation to minimize heat loss and repeat the investigation to calculate an average to reduce random error.

Question 36

What are the uses of energy resources?

Answer 36

Transport, Electricity Generation, Heating ## Footnote Examples include coal for electricity generation, gas for heating and electricity generation, petrol for transport, and wind power for electricity generation.

Question 37

What is a renewable energy resource?

Answer 37

A renewable energy resource is one that is being (or can be) replenished as it is used, meaning they won't run out. ## Footnote Examples include the Sun, Wind, Wave, Tidal, Geothermal, Hydroelectric, and Biofuel.

Question 38

What are non-renewable resources?

Answer 38

Non-renewable resources include fossil fuels and nuclear energy, which will eventually run out. ## Footnote The three fossil fuels are coal, oil, and gas.

Question 39

What environmental issues are caused by fossil fuels?

Answer 39

Fossil fuels release carbon dioxide when burned, contributing to greenhouse gases and global warming. ## Footnote They also release sulfur dioxide, which causes acid rain.

Question 40

What are the environmental impacts of renewable energy resources?

Answer 40

Renewable resources can cause damage to habitats and species when land is cleared for their construction.

Question 41

What is a reliable energy resource?

Answer 41

A reliable energy resource is one where we can predict how much energy it will produce in a set time period. ## Footnote Many renewable resources, like wind and solar, are not reliable due to their dependence on weather.

Question 42

How does electricity demand vary?

Answer 42

Demand for power varies by time of day and season.

Question 43

What are the characteristics of different power stations?

Answer 43

Some power stations, like nuclear and coal, are always on, while gas and hydroelectric can be turned on quickly when needed.

Question 44

What does 'evaluate' mean in the context of energy resources?

Answer 44

To evaluate means to give advantages and disadvantages of a resource.

Question 45

What should be included when evaluating energy resources?

Answer 45

Always state whether a resource is renewable, reliable, and emits carbon dioxide first.

Question 46

What is an advantage of nuclear energy?

Answer 46

You get a large amount of energy from a small mass of fuel.

Question 47

What is an advantage of hydroelectric energy?

Answer 47

Hydroelectric energy can be used to store energy.