Q&A - PSLE Science

[charsen]

Michaelia0816:

Charsen,


1)http://i45.tinypic.com/9kvvgn.jpg\">

Explain your answer in (a).

Even through I know how, but it is hard to explain, can you give me a good answer?


Links:
1) http://t.co/MkEfV9W8
2) http://t.co/y7MXhnYd
3) http://t.co/6fTNN4kr

Hi
Link 1:The chemical potential energy in peggy converted into kinetic energy + heat energy+sound energy when she hit the moving shuttercock.Thus,the shuttercock moved even more faster.Concept:energy conversions.

Link 2:Push force was applied on the stone when it is released from the catapult.As it goes up,the gravitational force causes it to pull the stone towards the ground.Concept:Forces/types of forces/uses of forces

Link 3:The option (c) is wrong.So,cancel all the answer which has option (c) and you'll find your answer.

Link 4:Answer(4).Since there is less heat from the surroundings to evaporate from the water bodies,evaporation process is decreased.(T) shows the evaporation process from river to the clouds.Thus,the answer is (4).

Always remember to read the question and relate it to your syllabus.Find the knowledge of concepts in each question.Hope this tip helps.
Cheers

[Michaelia0816]

Michaelia0816:

Again, Charsen,


I would like to seek help from you again,

Links:
1) http://t.co/6fTNN4kr
2) http://t.co/hj3plO5M

That all.

Charsen, ,pls help with the 4 more questions, I will post it later which I really dun know.

[Michaelia0816]

Thx!

[Michaelia0816]

Charsen,


1)
http://i45.tinypic.com/9kvvgn.jpg\">

Explain your answer in (a).
--------------------------------------------------------------------------------------
2)
http://t.co/4YkPbS51
--------------------------------------------------------------------------------------
3)
http://t.co/5JdTXHnk
--------------------------------------------------------------------------------------
4)
http://t.co/MdP20oDI
--------------------------------------------------------------------------------------
5)
http://t.co/oHVJRRHU


My apologies, it should be 5 more questions instead of 4.

[charsen]

[quote=\"Michaelia0816\"]Charsen,


1)
http://i45.tinypic.com/9kvvgn.jpg\">

Explain your answer in (a).
--------------------------------------------------------------------------------------
2)
http://t.co/4YkPbS51
--------------------------------------------------------------------------------------
3)
http://t.co/5JdTXHnk
--------------------------------------------------------------------------------------
4)
http://t.co/MdP20oDI
--------------------------------------------------------------------------------------
5)
http://t.co/oHVJRRHU


My apologies, it should be 5 more questions instead of 4. :sweat[quote]
Hi
Link 2:Answer is (3).Weight is caused by the force of gravity acting on it and thus,your mass will not change if you are on the moon but the weight does change.

Link 3:Answer is (3).Independent variable is exposed surface area.Dependent
variable is time taken for each towel to dry.Independent variable should always be at the x axis and the dependent variable will always be at the y axis.

Link 4:Answer is (1).The hot plate is a heat source which heats the water and cause it to evaporate.the sun's role in the water cycle is almost the same as the hot plate.The water droplets cannot be condensation,thus it should be rain as it falls from the clear plastic sheet.

Link 5:Answer is (1).(A) cannot be in the answer as Set-up R will take a longer time to heat up since there is more water in the container will result in more heat to boil.(b) cannot be the answer as when the water in both set-ups are in the same temperature,water in set-up r would have more heat than the other set-up.

For link 1, what do you man by explain in (a).There is no (a) in the question.
cheers

[Michaelia0816]

Thx, I kind of bad at this, >.<

[its888me]

ACS 2011 Prelim Paper, Section B, Q41:


http://i49.tinypic.com/2h3btzd.jpg\">
(b) Farmer Amos noticed that his maize plantation has been infested by rats. Without introducing any new species into the above food web, suggest a suitable and sage method that can help him overcome this problem.

Marking Scheme:
- Introduce owls into the community (1)
- Introduce snakes (0)
- Introduce snakes & owls (0)

Why is \"Introduce snakes\" getting a 0 marks since snakes will eat up the rats?

TIA!

[its888me]

its888me:

ACS 2011 Prelim Paper, Section B, Q41:


http://i49.tinypic.com/2h3btzd.jpg\">
(b) Farmer Amos noticed that his maize plantation has been infested by rats. Without introducing any new species into the above food web, suggest a suitable and sage method that can help him overcome this problem.

Marking Scheme:
- Introduce owls into the community (1)
- Introduce snakes (0)
- Introduce snakes & owls (0)

Why is \"Introduce snakes\" getting a 0 marks since snakes will eat up the rats?

TIA!

can someone help?

Many thanks!

[Sun_2010]

its888me:

ACS 2011 Prelim Paper, Section B, Q41:


http://i49.tinypic.com/2h3btzd.jpg\">
(b) Farmer Amos noticed that his maize plantation has been infested by rats. Without introducing any new species into the above food web, suggest a suitable and sage method that can help him overcome this problem.

Marking Scheme:
- Introduce owls into the community (1)
- Introduce snakes (0)
- Introduce snakes & owls (0)

Why is \"Introduce snakes\" getting a 0 marks since snakes will eat up the rats?

TIA!

I think the highlighted word is safe .
That is why cannot be more snakes ?

[charsen]

its888me:

ACS 2011 Prelim Paper, Section B, Q41:


http://i49.tinypic.com/2h3btzd.jpg\">
(b) Farmer Amos noticed that his maize plantation has been infested by rats. Without introducing any new species into the above food web, suggest a suitable and sage method that can help him overcome this problem.

Marking Scheme:
- Introduce owls into the community (1)
- Introduce snakes (0)
- Introduce snakes & owls (0)

Why is \"Introduce snakes\" getting a 0 marks since snakes will eat up the rats?

TIA!

Hi
In my point of view,introducing the snakes would harm other useful animals in the plantation.Not only that,the owl population would also increase,so you can say that both populations would compete for food,which results in the decrease in the number of snakes only.
cheers
Cheers