Q&A - PSLE Science

[pixiedust]

Hi all, what's your opinion of statement C - is it true ? and what's the reason ?

Thanks.
(topic : P6 forces)

http://i1197.photobucket.com/albums/aa424/pixie_dust8/ksp2012/sci1.jpg\">

[Nebbermind]

a) true, since a force is needed to push her up.

b) true, since the trampolin will stretch downwards when she land
c) not sure. when she is in contact with the trampolin, her speed would be zero at its lowest point. So definitely it has to increase for her to move up. But once she lose contact with the trampolin, her speed should be decreasing.

Anyone with an alternative explanation?

[mother777]

Hi guys,

I found this beautiful link which explains the energy conversion in different activities via graphics.

It is great to see something and understand. Hope you guys like it

http://www.science-animations.com/support-files/energy.swf

[mother777]

pixiedust:

Hi all, what's your opinion of statement C - is it true ? and what's the reason ?

Thanks.
(topic : P6 forces)

http://i1197.photobucket.com/albums/aa424/pixie_dust8/ksp2012/sci1.jpg\">

Hi,

actually i am bit confused by statement c.
it means the \"speed\" initially increases.
But formula for speed is dist/time.. how to show it is increasing or decreasing here?

wouldn't it be more relevant if the question mentions \" velocity or acceleration\" initially increases?

Because if this was the question, then I will agree to that statement..

what you guys think? and just wonder what the actual answer for this question given in the book?

[pixiedust]

Thanks Nebbermind and mother777 (thanks for sharing the useful link too) !

The answer to the questions stated statements A,B,C are all true ie (4).
However, I have doubts about statement C and trying very hard to relate it to the key concepts in forces.

jesschan:

Hi! Has anyone tried Aitong's 2011 CA1 MCQs? The answer sheet that I have seems to be full of mistakes. What are your answers to Questions 1,4, 5, 11 & 25?

Jesschan, here are my answers, can we discuss to find the right answer ?

Q1 : (1) 5 [different from ans sheet]
Q4 : (1) [same as ans sheet]
Q5 : (3) [same as ans sheet]
Q11: (1) [different from ans sheet]
Q25: (4) [different from ans sheet]

In addition, what is your answer for Q21 ?

[atutor2001]

Answer is (1)

[jesschan]

pixiedust:

Jesschan, here are my answers, can we discuss to find the right answer ?

Q1 : (1) 5 [different from ans sheet]
Q4 : (1) [same as ans sheet]
Q5 : (3) [same as ans sheet]
Q11: (1) [different from ans sheet]
Q25: (4) [different from ans sheet]

In addition, what is your answer for Q21 ?

Thanks, pixiedust. Agree with your answers except for Q5 which I think is ambiguous. Can it be (3) as well? Q4 was my mistake, misread the question. My answer for Q21 is (2).

[kitty2]

Deleted

[Winx5015]

Hi,


this question is found in my Pals are here - Science (energy) workbook.

Scientists are investigating a new type of wind power station, called the maglev wind turbine. By using repulsion between permanent magnets, the wind turbine is held in the air above the base of the machine. why does this save energy?

Thanks!

[anneshirleygilbert]

Winx5015:

Hi,


this question is found in my Pals are here - Science (energy) workbook.

Scientists are investigating a new type of wind power station, called the maglev wind turbine. By using repulsion between permanent magnets, the wind turbine is held in the air above the base of the machine. why does this save energy?

Thanks!

As the wind turbine is held in the air above the base of the machine, there is no friction, so there is no heat energy produced. Thus no energy is wasted.

Hope this helps.