Q&A - PSLE Science
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fightingmom:
The problem is \"what is air resistance?\", i.e. is air resistance a type of force? I recalled forces being classified into push, pull, magnetic, elastic spring, gravitational.... but no air resistance force.Hi,
Can help with the following question:
In an Archery lesson, John was holding a bow and arrow and trying to hit the bull's eye. Name the force(s) that is/are acting on the moving arrow towards the bull's eye.
My DD's answer is gravitational force and air resistance.
Answer sheet is gravity and friction.
Can anyone cfm whether friction is correct and my DD's answer on air resistance is correct or wrong?
TIA
Therefore, probably the syllabus does not recognise air resistance as a type of force. The most kiasu answer will be.
\"Air resistance caused by frictional force.\" I remembered science is \"positive marking\" so as long as there is no major conceptual error, once keyword is there, mark has to be given. -
atutor2001:
Eh... pardon me - so my DD answer is wrong right in this case ? can only secure 1/2 mark right ? :scratchhead:
The problem is \"what is air resistance?\", i.e. is air resistance a type of force? I recalled forces being classified into push, pull, magnetic, elastic spring, gravitational.... but no air resistance force.fightingmom:
Hi,
Can help with the following question:
In an Archery lesson, John was holding a bow and arrow and trying to hit the bull's eye. Name the force(s) that is/are acting on the moving arrow towards the bull's eye.
My DD's answer is gravitational force and air resistance.
Answer sheet is gravity and friction.
Can anyone cfm whether friction is correct and my DD's answer on air resistance is correct or wrong?
TIA
Therefore, probably the syllabus does not recognise air resistance as a type of force. The most kiasu answer will be.
\"Air resistance caused by frictional force.\" I remembered science is \"positive marking\" so as long as there is no major conceptual error, once keyword is there, mark has to be given. -
fightingmom:
Your DD is correct. Air resistance is a force, a frictional force between the surface of the arrow and air. Frictional force between a moving object through liquid is called drag or drag force. Therefore, both air resistance and drag are Frictional Force. However, I am not sure if it is covered in primary school syllabus and some schools are silly enough to considered them as wrong if used.
Eh... pardon me - so my DD answer is wrong right in this case ? can only secure 1/2 mark right ? :scratchhead:
For such cases, I used to coach my kids to be super kiasu by putting in both key words, i.e. \"air resistance\" and \"frictional force\" in the answer. The kiasu answers can be :
\"Air resistance, which is a frictional force between the surface of contact between the arrow and air.\"
or
\"Frictional force between the surface of the arrow and air which is also called air resistance.\"
However, knowing how school's answer keys are like, there is no point arguing with them. However, I believe it will be marked as correct in PSLE. -
atutor2001:
ok ok ... :thankyou: so much for your explanation and clarification ! Appreciate your help.
Your DD is correct. Air resistance is a force, a frictional force between the surface of the arrow and air.fightingmom:
Eh... pardon me - so my DD answer is wrong right in this case ? can only secure 1/2 mark right ? :scratchhead:
For such cases, I used to coach my kids to be super kiasu by putting in both key words, i.e. \"air resistance\" and \"frictional force\" in the answer. The kiasu answers can be :
\"Air resistance, which is a frictional force between the surface of contact between the arrow and air.\"
or
\"Frictional force between the surface of the arrow and air which is also called air resistance.\"
However, knowing how school's answer keys are like, there is no point arguing with them. However, I believe it will be marked as correct in PSLE. -
G Tan:
The answer is (4) because the size of the population (in this case the question asked \"how many\") includes all the individual organisms adult and young. For example if there are five frogs and ten tadpoles in a pond, the population of frogs will be 15.mom-of-2:
![](\"http://i49.tinypic.com/2ur8rrq.jpg\")
http://i49.tinypic.com/2ur8rrq.jpg\"> Can I ask if anyone know the answer to this question. The answer is 4 but I think it's wrong.
mom-of-2:
The answer is 1
Hope this helps. -
PSLE 2012:
The answer is (4) because the size of the population (in this case the question asked \"how many\") includes all the individual organisms adult and young. For example if there are five frogs and ten tadpoles in a pond, the population of frogs will be 15.G Tan:
[quote=\"mom-of-2\"]
mom-of-2:
The answer is 1
The answer is definitely 1.
It is asking how many populations? not the population size?
Hope this helps.[/quote] -
If according on the question, it should be 1 instead!
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Which of the following activities below involve(s) only a push?
A: stapling a few pieces of paper together
B: writing with a pen
plucking a flower
bouncing s basketball
(1) A only
(2) A and D only
(3) A, B and D only
(4) B, C and D only -
Is the answer A, B and D?
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The answer is (2) A and D but my dd answer is (3) A, B and D. However, I don’t know how to explain to her as I thought her answer was right.
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