Q&A - PSLE Science

[P5G]

Please help.


http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA2-Nanyang.pdf


Question 18 - Energy
Worksheet answer is (1). Should the correct answer be (2)?


Question 21 - Electricity
Worksheet answer is (1). Should the correct answer be (2)?


TIA.

[Hifive]

Hi all


Please help with this question:

http://www.flickr.com/photos/62186744@N04/6028721608/

Thanks in advance!

[IMTRYINGSTUFF]

[quote=\"Hifive\"]Hi all


Please help with this question:

http://www.flickr.com/photos/62186744@N04/6028721608/

Thanks in advance![/q
b.)The magnetic force of attraction is no longer present and so the sphere is no longer attracted to the toy. The sphere then is pulled by gravity and falls to the ground.
c.) No, it cannot. Steel is a magnetic material, so it prevents the magnetic force of attraction from passing through. The sphere will not be able to be attracted to the toy and so he toy would not work.

I think these are the answers in the view of a P6 student

[atutor2001]

Hifive:

Hi all


Please help with this question:

http://www.flickr.com/photos/62186744@N04/6028721608/

Thanks in advance!

This is a good example of how irresponsible primary sc dept can be. It is common knowledge that without any restraint to hold back the ball, it will be attracted to the \"toy\" (inverse square law). It will not remain floating in the air as claimed. Therefore, the situation as shown in the question cannot happen... or did I miss something new that is being thought nowadays.

[IMTRYINGSTUFF]

P5G:

Please help.


http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA2-Nanyang.pdf


Question 18 - Energy
Worksheet answer is (1). Should the correct answer be (2)?


Question 21 - Electricity
Worksheet answer is (1). Should the correct answer be (2)?


TIA.

Q18: I agree with the answer. The sun's heat is concentrated on the paper and so the heat energy goes to the paper. The paper burns, so there is fire. The fire has light energy. So the energy conversion is HEAT ENERGY TO LIGHT ENERGY.

Q21: I agree with the answer. Closing S3 would be no use to making the bell ring. S1 and S2 makes the bell ring.

[IMTRYINGSTUFF]

atutor2001:

Hifive:

Hi all


Please help with this question:

http://www.flickr.com/photos/62186744@N04/6028721608/

Thanks in advance!

This is a good example of how irresponsible primary sc dept can be. It is common knowledge that without any restraint to hold back the ball, it will be attracted to the \"toy\" (inverse square law). It will not remain floating in the air as claimed. Therefore, the situation as shown in the question cannot happen... or did I miss something new that is being thought nowadays.

Maybe the force of gravity and the magnetic force of attraction are the same in this toy and so they cancel seach other out and the sphere remains floating in the air, like if you put a sphere in space and not move it.

[Hifive]

IMTRYINGSTUFF:

Hifive:

Hi all


Please help with this question:

http://www.flickr.com/photos/62186744@N04/6028721608/

Thanks in advance![/q
b.)The magnetic force of attraction is no longer present and so the sphere is no longer attracted to the toy. The sphere then is pulled by gravity and falls to the ground.
c.) No, it cannot. Steel is a magnetic material, so it prevents the magnetic force of attraction from passing through. The sphere will not be able to be attracted to the toy and so he toy would not work.

I think these are the answers in the view of a P6 student

Hi IMTRYINGSTUFF

Many thanks for your explanation.

[atutor2001]

IMTRYINGSTUFF:

Maybe the force of gravity and the magnetic force of attraction are the same in this toy and so they cancel seach other out and the sphere remains floating in the air, like if you put a sphere in space and not move it.

That is the ideal equilibrium which cannot happen in real life because of

1) air around the sphere (frictional force)
2) uneven distribution of the mass of the sphere with the magnet in it
3) the magnetic force is not a single \"point\" force but a distribution of many forces..in many directions..
...

It is not good to mislead young children. I still remember once a cute little guy in this forum asked : Can penguins' fly? - because he saw a BBC youtube vido showing penguins flying.

[chrisu]

For Q21, the correct answer is (2). S1 and S3 closed. Though S1 is the only switch needed to be closed for bell to work, S3 can be closed as given by the answers even it is not required.


Once S2 is closed, the bell will not ring.

P5G:

Please help.

http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA2-Nanyang.pdf


Question 18 - Energy
Worksheet answer is (1). Should the correct answer be (2)?


Question 21 - Electricity
Worksheet answer is (1). Should the correct answer be (2)?


TIA.

[Nebbermind]

atutor2001:

IMTRYINGSTUFF:

Maybe the force of gravity and the magnetic force of attraction are the same in this toy and so they cancel seach other out and the sphere remains floating in the air, like if you put a sphere in space and not move it.

That is the ideal equilibrium which cannot happen in real life because of

1) air around the sphere (frictional force)
2) uneven distribution of the mass of the sphere with the magnet in it
3) the magnetic force is not a single \"point\" force but a distribution of many forces..in many directions..
...

It is not good to mislead young children. I still remember once a cute little guy in this forum asked : Can penguins' fly? - because he saw a BBC youtube vido showing penguins flying.

this magnet qn wld probably makes sense if the magnet in the toy is placed at the bottom rather than top.

then using the principle of unlike poles, the ball will float (but I think still need to be held vertically in place by a cylinder).