Q&A - PSLE Science

[charsen]

MommyDearest:

MommyDearest:

http://i45.tinypic.com/rksmfn.jpg\">


Qtn quoted here for better visibilty.

<<Shawn wanted to find out how much force was needed to overcome the attraction of different materials which were attracted to a strong magnet. The materials are of similar size. He set up the experiment as shown below.

(see image above)

He pulled on the spring balance until the material was separated from the magnet. The readings on the spring balance were recorded as shown below.

Material-------->Readings on the Spring Balance (unit force)
P---------------->45
Q---------------->60
R---------------->30
S---------------->45

What conclusions could he make from the above readings ?

A: Q is the best material for magnetic attraction.
B: R is made from a heavier material than material Q.
P and S are made from the same magnetic material.
R is easier to be magnetized as compared to material P.

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

Can someone please advise on the answer for the above question ? Many thanks in advance!

Hi
The answer should be 1 as option b is telling that this experiment variable is the materials mass which is totally incorrect.Once b is false,2 and 4 are stroked off.So,to answer this question ,identify the independent variable in this experiment.
Charsen 2.0

[SAHMwith2boys]

arowana:

atutor2001:

[quote=\"SAHMwith2boys\"]Hi all, need help with the following question:


Which of the following objects are not affected by gravitational force?
A. A bird flying in the sky
B. A man lying on the floor
C. A balloon rising into the sky

1. B only
2. A and C only
3. A and B only
4. None of the above

The answer given was (3), but couldn't understand why??

The answer should be (4) because if there is no gravitational force acting on the objects :
A. A bird flying in the sky can stay in the sky without flapping its wings
B. A main lying on the floor can be lifted up with our little finger.
C. A balloon rising into the sky need not be filled with a light gas but can be filled with stone and by give an upward push, it will continue to rise.

Fully agree with your answer and explanation.[/quote]Thanks all, I'll relay this message to DS...

[SAHMwith2boys]

http://i49.tinypic.com/14ax1yc.jpg\">

Qn: State 2 advantages of using this pulley system.
Ans:
1. Less effort is needed to lift the load.
2. It changes the direction of the force.

Can someone explain what is the meaning of the 2nd point in the answer? Thanks.

[Sun_2010]

SAHMwith2boys:

http://i49.tinypic.com/14ax1yc.jpg\">

Qn: State 2 advantages of using this pulley system.
Ans:
1. Less effort is needed to lift the load.
2. It changes the direction of the force.

Can someone explain what is the meaning of the 2nd point in the answer? Thanks.

Is this from an old paper?

I tot simple machines have been removed from the syllabus from 2010 psle batch?

[SAHMwith2boys]

Sun_2010:

SAHMwith2boys:

http://i49.tinypic.com/14ax1yc.jpg\">

Qn: State 2 advantages of using this pulley system.
Ans:
1. Less effort is needed to lift the load.
2. It changes the direction of the force.

Can someone explain what is the meaning of the 2nd point in the answer? Thanks.

Is this from an old paper?

I tot simple machines have been removed from the syllabus from 2010 psle batch?

Really? Can someone confirm this? I have no idea, this is from one of my DS paper that he is working on...

[zinc6539]

SAHMwith2boys:

http://i49.tinypic.com/14ax1yc.jpg\">

Qn: State 2 advantages of using this pulley system.
Ans:
1. Less effort is needed to lift the load.
2. It changes the direction of the force.

Can someone explain what is the meaning of the 2nd point in the answer? Thanks.

I don't know what's in the syllabus now. But just to answer your question, point 2 means that one is now pulling in the direction of the gravitational force (downwards) instead of opposite (upwards). Hence leading to point 1.

[SAHMwith2boys]

zinc6539:

SAHMwith2boys:

http://i49.tinypic.com/14ax1yc.jpg\">

Qn: State 2 advantages of using this pulley system.
Ans:
1. Less effort is needed to lift the load.
2. It changes the direction of the force.

Can someone explain what is the meaning of the 2nd point in the answer? Thanks.

I don't know what's in the syllabus now. But just to answer your question, point 2 means that one is now pulling in the direction of the gravitational force (downwards) instead of opposite (upwards). Hence leading to point 1.

Thanks for your answer. I went to MOE website to check, only found syllabus for yr 2008 science...anyway, I think it's good info for DS to know...

[pecalis]

Sun_2010:

SAHMwith2boys:

http://i49.tinypic.com/14ax1yc.jpg\">

Qn: State 2 advantages of using this pulley system.
Ans:
1. Less effort is needed to lift the load.
2. It changes the direction of the force.

Can someone explain what is the meaning of the 2nd point in the answer? Thanks.

Is this from an old paper?

I tot simple machines have been removed from the syllabus from 2010 psle batch?

Agree tt Simple Machines no longer in Sc syllabus. They will learn it in Sc Sch though...

[bestwishes]

Simple machine is not in the current pri sc syllabus. HOWEVER, as there are information or data provided in the qn (picture and table), the answers can be deduced easily. Hence, this qn is not considered out of syllabus qn.

[keinic]

Hi


Appreciate if someone could help with the following question extracted from NanHua 2012 CA1 paper. My DS's answer is 3 but the answer given is 2. Tks.

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