4.16

11:55
· 4.16 understand the energy transfers involved in generating electricity using:
· wind
· water
· geothermal resources
· solar heating systems
· solar cells
· fossil fuels
· nuclear power

>

>

>

Inserted from: >
[cid:image001.png@01CC7867.D58B1BD0]
[cid:image002.png@01CC7867.D58B1BD0]
[cid:image003.png@01CC7867.D58B1BD0]
[cid:image004.png@01CC7867.D58B1BD0]
[cid:image005.png@01CC7867.D58B1BD0]
[cid:image006.png@01CC7867.D58B1BD0]
[cid:image007.png@01CC7867.D58B1BD0]
[cid:image008.png@01CC7867.D58B1BD0]
[cid:image009.png@01CC7867.D58B1BD0]
[cid:image010.png@01CC7867.D58B1BD0]
[cid:image011.png@01CC7867.D58B1BD0]
[cid:image012.png@01CC7867.D58B1BD0]

wind energy story.swf Download this file

Teacher Presentation.ppt Download this file

Srinakarin Hydro Dam, Kanchanaburi.avi Watch on Posterous

See the full gallery on Posterous

4.17 Answers

>

Inserted from: >
[cid:image001.png@01CC786A.1E85E660]
[cid:image002.png@01CC786A.1E85E660]

ADs and DISADs of ENERGY SOURCES-answers.docx Download this file

See the full gallery on Posterous

Entrance Activity

>

Inserted from: >
[cid:image001.png@01CC7864.94C87690]

Starter.ppt Download this file

: Starter for 4.16

DragnDropEnergy.swf Download this file

>

: P4 IGCSE Physics Student Objectives

>

Inserted from: >
[cid:image002.png@01CC7862.AD9DA660]

IGCSE Physics Student Objectives for Unit 4 - New Specification.doc Download this file

See the full gallery on Posterous

: Power questions

PFY, p. 120

[cid:image001.png@01CC7861.A7A2D8D0]

[cid:image002.png@01CC7861.A7A2D8D0]

power is the rate of doing work

power (in Watrs) = work done (in joules ) / time (in seconds)

1 watt is the rate of working of one joule per second 13. P = e/t
P = 1000/ 5
P = 200 W

14. Wd = F x d P = 600/6 P = 100 W 15. Wd = 3000 x 10 = 30,000 J 30000 / 4 = 7500 watts per second 7.5 kw per second

See the full gallery on Posterous

4.15

· 4.15 use the relationship between power, work done (energy transferred) and time taken:

power = work done P = Wd

time taken t

P = Wd / t

P = E / t

P = Power (Watts, W)

Wd = Work Done (Joules, J)

E = Energy Transferred (Joules, J)

t = Time (s)

4.14

11:53
· 4.14 describe power as the rate of transfer of energy or the rate of doing work

"Rate" just means "divided by time" (see Entrance Activity)

So

Power = Energy / Time

or

Power = Work done / Time

4.14 Entrance Activity Answers

Tell the person next to you...
· You can run up the stairs in the Science block in 30 seconds.
· Mr. Roff can run up the stairs in the Science block in 20 seconds.
· Who is the most powerful? Why?
· Mr Roff. He does more work running up the stairs (because has a higher weight) in a shorted time so he is more powerful

· It takes 2 minutes to fill the 20 litre sinks in this room with water.
· How fast is the sink filling?
· 10 litres/min
· At what rate is the sink filling?
· 10 litres/min
· How long would it take to fill a 10 litre sink?
· 1 min

4.13

· 4.13 understand how conservation of energy produces a link between gravitational potential energy, kinetic energy and work

>

Inserted from: >
[cid:image001.png@01CC72E7.3B356A70]
[cid:image002.png@01CC72E7.3B356A70]
[cid:image003.png@01CC72E7.3B356A70]
[cid:image004.png@01CC72E7.3B356A70]

CoE.ppt Download this file

See the full gallery on Posterous

Questions

PFY pg. 121

19. a) W= m x g
W = 50 x 10
W = 500 N

b) GPE = mgh
GPE = 50 x 10 x 4 GPE = 2000J

total energy at the beginning = total energy at the start c) KE = 2000J

collins pg. 91

Q3: a) GPE = mgh
GPE = 35 x 10 x 30 GPE = 10, 500J KE = 1/2 x 35 x v squared 10,500 = 1/2 x 35 v squared b) V 2= 600
V= 24.5 m/s c) friction

4.12

· 4.12 recall and use the relationship:

kinetic energy = ½ × mass × speed2

KE = ½ × m × v2
>

Inserted from: >
[cid:image001.png@01CC6D6B.528A10D0]
[cid:image002.png@01CC6D6B.528A10D0]
[cid:image003.png@01CC6D6B.528A10D0]
[cid:image004.png@01CC6D6B.528A10D0]

KE formula.ppt Download this file

4.11

· 4.11 recall and use the relationship:

gravitational potential energy = mass × g × height

GPE = m × g × h

>

>

>

Inserted from: >
[cid:image001.png@01CC6D6B.4B1494B0]
[cid:image002.png@01CC6D6B.4B1494B0]
[cid:image003.png@01CC6D6B.4B1494B0]
[cid:image004.png@01CC6D6B.4B1494B0]

GPE formula.ppt Download this file

4B2 highest to lowest GPE.swf Download this file

4B2 GPE calculation of car moving downhill.swf Download this file

4.10

________________________________________
From: Lydia Anna Foley
Sent: Wednesday, September 07, 2011 2:10 PM
To: lydiafoley@posterous.com
Subject: 4.10 ((nogallery))

· 4.10 understand that work done is equal to energy transferred

PFY p.112

[cid:image001.png@01CC6D66.70900440]
a) the work done (measured in joules) is equal to the force (in newtons) multipulied by the distance moved (in metres)
b) 1 joule is the work done when a force of one newton moves through a distance of one metre ( in the direction of the force). work dorn + energy transferred.

[cid:image002.png@01CC6D66.70900440]
word done = 5 x 2 = 10 J

[cid:image003.png@01CC6D66.70900440]
work done =

500 N x 40m = 20,000 J
Collins p. 91
W = m x g W = 400 x 10
W = 4000n

Wd = F x d 50000J = 4000 x d d = 12.5 m

[cid:image004.png@01CC6D66.70900440]

Plenary Answers

4.10

· 4.10 understand that work done is equal to energy transferred

PFY p.112

[cid:image001.png@01CC6D66.70900440]
a) the work done (measured in joules) is equal to the force (in newtons) multipulied by the distance moved (in metres)
b) 1 joule is the work done when a force of one newton moves through a distance of one metre ( in the direction of the force). work dorn + energy transferred.

[cid:image002.png@01CC6D66.70900440]
word done = 5 x 2 = 10 J

[cid:image003.png@01CC6D66.70900440]
work done = 500 N x 40m = 20,000 J
Collins p. 91
= 20 kj

[cid:image004.png@01CC6D66.70900440]