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SHHS - Year 9 Physics > Energy > Flashcards

Flashcards in Energy Deck (37)
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1

Name 5 ways you can reduce energy loss in your home.

Choose from:

  • loft insulation,
  • cavity wall insulation,
  • double glazing,
  • draught excluders, 
  • silver foil behind radiators.
  • carpet, rugs and underlay

2

Give 2 advantages of using fossil fuels to make electricity.

Advantage 1. Fossil fuels are readily available. Advantage 2. Gas power stations have a short start up time meaning the power station can quickly respond to an increased demand.

3

Name 4 energy resources that are renewable.

Chosse 4 energy resources that are renewable

from biofuel,

wind,

hydro-electricity, 

geothermal,

the tides,

the Sun

and water waves.

4

A crane does 15,000J of work in 30 seconds. What is its power?

Power = work done/time taken

=15,000/30

= 500W

5

Give 2 advantages of using renewable sources to make electricity

This will depend on the renewable source used but in general:

Advantage 1. No carbon dioxide is released so the production of energy does not add to climate change. Advantage 2. renewable sources are or can be continuously replaced and so will never run out.

6

What will affect how fast a building loses heat energy?

The rate of cooling of a building
is affected by the thickness and thermal conductivity of its walls.

7

Heat energy only flows in which direction?

From hotter objects to colder objects.

8

What is the equation to find gravitational potential energy?

9

Would you want a high or low specific heat capacity for a liquid used to fill a radiator? Why?

You would want a high specific heat capacity for a liquid used to fill a radiator because it would store a lot of energy and cool down slowly.

10

What is specific heat capacity?

The energy needed to raise the temperature of 1 kg of a substance by 1 degree.

11

What is power measured in?

Power is measured in Watts.

1 Watt = 1 Joule per second.

12

What is a renewable energy resource?

A renewable energy resource is one that is being

(or can be) replenished as it is used

13

What is meant by Power?

Power is a measurement of how quickly work is done. The faster you do work, or transfer energy, the greater your power.

14

If a substance has a high specific heat capacity, what does this tell you about the amount of energy it stores?

Substances with a high specific heat capacity take a lot of energy to heat up, so can store a lot of energy.

15

What is meant by Work Done?

Work Done is the energy transferred when a force acts over a certain distance.

16

What does thermal conductivity mean?

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

17

If a substance has a high specific heat capacity, what does this tell you about how it heats up?

Substances with a high specific heat capacity take a lot of energy to heat up, so will heat up slowly.

18

Describe the energy change of an object accelerated by a constant force

The object will gain speed and so gains kinetic energy.

19

A car has a mass of 1000kg and a speed of 10m/s. What is its kinetic energy?

KE = 1/2 mv2

KE = 1/2 x 1000 x 102

= 50,000J

20

Describe the energy changes in a vehicle slowing down

As the vehicle slows down it loses kinetic energy. This is converted into heat due to friction with the air and the brake blocks and the tyres.

21

You will be given the equation to calculate the energy in a coiled spring. Can you rearrange this to find the spring constant?

 

The spring constant k =E/ 0.5 x e2

22

Name 4 energy resources that are non-renewable.

Oil, coal, gas and nuclear fuels such as Uranium are all non-renewable.

23

What is meant by 'efficiency'?

A measurement of the useful energy output as a percentage of the total energy input.

Eg. a light bulb that converts 50 J of energy into light out of 200 J of electricity supplied would be 25% efficient.

24

If a substance has a high specific heat capacity, what does this tell you about how it cools down?

Substances with a high specific heat capacity store a lot of energy so will cool down slowly.

25

Describe the energy changes when a moving object hits an obstacle

The moving object has Kinetic Energy. When it hits an obstacl it loses this KE (and comes to a sudden stop). The energy is converted into sound, possibly light and heat energy and possible some KE if the obstacle moves.

26

Rearrange:

work done = force x distance

so that it is:force =

You should get: force = work done/distance.

27

Give 2 advantages of using nuclear fuels to make electricity

Nuclear fuels such as Uranium and Plutonium release energy without being burned.

Advantage 1. Nuclear fuel releases a lot more energy per kg than a fossil fuel.

Advantage 2. As nuclear fuel does not need to be burnt to release energy it does not release CO2 and add to climate change.

28

Give 2 disadvantages of using nuclear fuels to make electricity

Nuclear fuels such as Uranium and Plutonium release energy without being burnt.

Disadvantage 1. Nuclear fuel produces nuclear waste which remains radiaoactive for 1000's of years. This waste is a cancer risk and needs to be strored safely away from people.

Disadvantage 2. Nuclear power stations are expensive to build and decomission (break up at the end of their life).

29

Describe the energy changes when an object is projected upwards

At the start of its journey the object, lets imagine that it's a ball, will be going the fastest it will travel (it has maximum KE). As it gets higher it slows down (loses KE)  This kinetic energy is converted to GPE, the ability to fall. At the top of its arc the ball has maximum GPE but zero KE. The ball then starts to fall to earth, gaining speed and KE but losing GPE.

30

What happens to kinetic energy if:

(a) the mass is doubled?

(b) the speed is doubled?

KE = 1/2 mv2 so

(a) KE doubles

(b) KE quadruples