Q&A - PSLE Science
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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.
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(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'.
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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.
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how come the school teacher didn't run thru the papers and make the kids do correction? :scratchhead:
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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. -
zombie:
i would think that the teacher circled the \"iron\" word because though ur ds wrote iron core but his explanation is about if steel core is used, then it will.. etc.@ 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'.
sorry to ask again, please help me with the graph question
posted on Wed Nov 07, 2012 1:56 pm
Thank you !
students must be reminded not to give a wrong explanation. if choose A, need to explain why have to choose A and not why cannot choose B. -
zombie:
a) ball w as it travelled the shortest distance because the friction between the ball surface and the ground is the greatest.another question,
what are the key words required ? DS seems to have verbal constipation in asnwering these questions. Please help. thanks.
(use friction between surface 1 and surface 2, produce is a wrong word to use)
b) he can release the ball at a higher position on the ramp. the higher the position of the ball being released, the greater the gravitational potential energy it possessed, hence converted to more kinetic energy to move to a longer distance.
hope it helps..
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