Q&A - PSLE Science
-
@atutor2001: Thanks! Physics puzzles are fun to think about.
verykiasumummy:
That's what I think, but I haven't done calculations for the rolling case to confirm it. The basic idea from interpreting that last equation I gave is that air resistance depends only on speed, not mass. Therefore, comparing objects at the same speed, heavy objects can \"overcome\" air resistance more easily than light ones - they're slowed down less by air resistance. So they accelerate faster than light objects.so does it mean that the heavier object will reach the ground first no matter whether is rolling down the ramp or free falling from a height??
Still, it's important to keep sight of the original principle, which is that objects fall (accelerate) at the same rate, regardless of their masses. -
Please help me with the P6 prelim question.
![](\"http://i49.tinypic.com/mh6aa.jpg\")
http://i49.tinypic.com/mh6aa.jpg\">
(a)\tExplain why the paper clips fell off the iron core, but not off the steel core.
(b)\t In a junkyard, an electromagnet is used to attract an old car before dropping it off at another place.
Is the iron core or steel core more suitable for use as the core of an electromagnet? Give a reason for your answer. -
![](\"http://i47.tinypic.com/33otkt0.jpg\")
The temperature cannot suddenly plunge to 10 degrees within 2 minutes, or lose heat to the surrounding within a short period of time, unless ice cubes are dropped into the water.
how to go about answering this question ? -
zombie:
hi offering my help :Please help me with the P6 prelim question.
(a)\tExplain why the paper clips fell off the iron core, but not off the steel core.
(b)\t In a junkyard, an electromagnet is used to attract an old car before dropping it off at another place.
Is the iron core or steel core more suitable for use as the core of an electromagnet? Give a reason for your answer.
a) the iron core loses its temporary magnetism when the power switch is turned off as the electric current flowing through it has stopped and it is no longer an electromagnet. however, the steel core still retains some magnetism after the power switch is turned off, hence, it was still able to attract the paper clips.
b) the iron core will be more suitable because when the power is turned on, the iron core will become an electromagnet that will attract the car and move it to another place, where the power will be turned off to drop the car. as the iron core loses its magnetism once the power is turned off, it could drop the car at its new location and turn back to move another car. -
@ verykiasumummy, many thanks for your answer.
But still am still puzzle, why DS answer is marked incorrect by his teacher
and why his teacher circle the word 'iron'.
![](\"http://i46.tinypic.com/r8xg1w.jpg\")
sorry to ask again, please help me with the graph question
posted on Wed Nov 07, 2012 1:56 pm
Thank you ! -
zombie:
Think I ever come across this....like ice or something very cold being added to the water...started to melt/heat u...bringing the temp down...then when all melted, the water temp start to rise again.
The temperature cannot suddenly plunge to 10 degrees within 2 minutes, or lose heat to the surrounding within a short period of time, unless ice cubes are dropped into the water.
how to go about answering this question ? -
another question,
what are the key words required ? DS seems to have verbal constipation in asnwering these questions. Please help. thanks.
![](\"http://i49.tinypic.com/2rxz5fo.jpg\")
![](\"http://i45.tinypic.com/2zq77v4.jpg\")
-
how come the school teacher didn't run thru the papers and make the kids do correction? :scratchhead:
-
zombie:
another question,
what are the key words required ? DS seems to have verbal constipation in asnwering these questions. Please help. thanks.
the question b mentions that it should be done without any change in apparatus. So increasing the height of the ramp (actually the incliation of the ramp) would be considered a change in the apparatus.
Which school paper ? Quite tricky question :evil: -
zombie:
some ice cubes / ice water / cold water has been added to the beaker.
The temperature cannot suddenly plunge to 10 degrees within 2 minutes, or lose heat to the surrounding within a short period of time, unless ice cubes are dropped into the water.
how to go about answering this question ?
the answer is straight forward. many questions in p5 and p6 test papers are similar like this.
Hello! It looks like you're interested in this conversation, but you don't have an account yet.
Getting fed up of having to scroll through the same posts each visit? When you register for an account, you'll always come back to exactly where you were before, and choose to be notified of new replies (either via email, or push notification). You'll also be able to save bookmarks and upvote posts to show your appreciation to other community members.
With your input, this post could be even better š
Register Login
