Q&A - PSLE Science

[atutor2001]

add another word siao

[Tang]

Ash001:

I have another question. Also from the Prelim paper


My son chose 2.
School answer is 1.

It seems different people have different intepretation for this qns.
Justification make below is base on understanding that the A/B/C is at that state
Ans 1 : Possible that B is solid @19
Ans 2 : YES for B to be liquid @84. Possible that C to be liquid @84

When I ask some of my friend, some of them chose Ans1, that was because their interpretation was A/B/C turn to that state at that temperature.

When I read the question once again, it did not explicily mention that.


http://i54.tinypic.com/1zcoahz.jpg\">

Hi,

From the data provided, it is Not Possible To Tell that A is a Solid.
Similarly, it is also Not Possible To Tell that C is a Liquid.

So either (1) or (2) can be accepted as correct.

If I were your son, I would ask the teacher for the 2 marks. Usually, our teachers will either accept both answers as correct or they will void the question and the marks will be adjusted based on total of 98.

[benleetube]

Hi there,


Please help me on the following question.

Which of the following statements is/are false?

A. There is no friction between two smooth surfaces.
B. There are forces acting on a stationary car on a slope.
C. Gravitational force acts only on objects placed above the ground.

The correct answer is A&C. But my answer is A,B and C.

Can anyone explain why? TIA!

[elkniwt]

Hi,


Need help on this qn :

Should the ans be (2) or (3)? Pls advise. Thanks.
http://i56.tinypic.com/oshfki.jpg\">

[Tang]

benleetube:

Hi there,


Please help me on the following question.

Which of the following statements is/are false?

A. There is no friction between two smooth surfaces.
B. There are forces acting on a stationary car on a slope.
C. Gravitational force acts only on objects placed above the ground.

The correct answer is A&C. But my answer is A,B and C.

Can anyone explain why? TIA!

A - False.
There is always friction between two surfaces as long as they are in contact.

B - True
On a slope, the forces acting on the stationary car are gravitational force and frictional force.

C - False
Below ground, gravity is also acting on objects (othewise the objects will float up or pop out of the ground!).

[Tang]

elkniwt:

Hi,


Need help on this qn :

Should the ans be (2) or (3)? Pls advise. Thanks.
http://i56.tinypic.com/oshfki.jpg\">

From the foodweb, A is the food producer. B is a herbivore while C is a omnivore.
C (a predator) preys on B (a prey).
Eating plants cannot be considered as a predator. So B is not a predator.
So answer is (2) - C only.

[stary]

Part 1

Hi all,
Need explanation for some questions.

F1RST Question:
(MGS/CA1/Primary 5/2009)
Question 14:

Lionel planted some seeds in a pot. He watered them every day. After a few weeks, plants grew in the pot. Later, the plants died. Which of the following is/are correct conclusion(s) of this experiment?

A: Plants can grow over time.
B: Plants come from seeds.
Plants will die.
Plants need water.

1) A only
2) A and B
3) A, C and D
4) B, C and D

My answer: 3
Answer sheet: 2
Whose is correct (and why?)

[stary]

Tang:

elkniwt:

Hi,


Need help on this qn :

Should the ans be (2) or (3)? Pls advise. Thanks.
http://i56.tinypic.com/oshfki.jpg\">

From the foodweb, A is the food producer. B is a herbivore while C is a omnivore.
C (a predator) preys on B (a prey).
Eating plants cannot be considered as a predator. So B is not a predator.
So answer is (2) - C only.

Hi Tang,

It is not necessary that 'A' must be a food producer. It can be a prey too.

Best Regards.

[stary]

Part 2

Hi all,
Need explanation for some questions.

2ECOND Question:
(Ai Tong/SA1/Primary 5/2009)
Question 14:

Which statement(s) about germination of a seed is/are correct?

A: During germination, the seed needs air, sunlight, water, food and warmth.
B: A seed does not need to make food.
Water is needed for germination to occur.
Fertiliser must be added to the seed for germination to take place.

1) C only
2) A and C
3) B and C
4) A, C and D

My answer: 3
Answer sheet: 1
Whose is correct? (And why?)

[stary]

My explanation for the above:


I chose B as the seedling did not have first leaves to make its own food so it depends on the seed leaves for food.