PSLE 2012 - Science
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Fishes die
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biniv300:
Can the ans be:
My ans is he should see which section the fishes swamfantasy1:
HI
How abt section (B) qn
Something abt the type of colour used for photosynthesis. For Part (C) when they removed the water plants, what observation will the person see to ensure result at part (B) is correct?
Is my ans correct?
My friend says my ans is correct and tis ques came in a schools 2009 prilim
The number of fish in each section. -
Where is Charsen ah???
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Concerned student:
I also777:
[quote=\"fantasy1\"]a only - swollen stem
(b) short root
(c) broad leaves
she chose only (a)
I also chose swollen stem
[/quote]Can't be short roots 'coz they will grow deep into the soil to collect more water and mineral salts.Broad leaves is also wrong as broad=more exposed surface area.Thus,the stomata will tend to lose more water.Remember,this Plant H lives in a desert-a hot and humid place.
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GLORYmum:
Where is Charsen ah???
:offtopic: -
thesjarox:
The force of friction is always exerted in a direction that opposes movement or potential movement between the two surfaces,
Confirmed with teacher-A,B and C.vaidyanathan padmini:
How about friction question from McQ.....
My dd's answer is only C as friction opposes motion...
Only the box in c is moving so it should have friction
Friction also acts on stationary objects. That's why forces have to overcome the friction before being able to move the object. Also, if there were no friction acting on an object,the object would glide across the surface, like ice, and would never stop.
Thus, A is also correct.
For B: Potential movement
For Movement
For A: non
So answer should be: B &C -
RVHS:
The force of friction is always exerted in a direction that opposes movement or potential movement between the two surfaces,
Confirmed with teacher-A,B and C.thesjarox:
[quote=\"vaidyanathan padmini\"]How about friction question from McQ.....
My dd's answer is only C as friction opposes motion...
Only the box in c is moving so it should have friction
Friction also acts on stationary objects. That's why forces have to overcome the friction before being able to move the object. Also, if there were no friction acting on an object,the object would glide across the surface, like ice, and would never stop.
Thus, A is also correct.
For B: Potential movement
For Movement
For A: non
So answer should be: B &C[/quote]
My answer for this question is (4) A, B & C. I thought about the surfaces in contact since if there was no friction the wooden block would be sliding around instead of remaining stationary. -
RVHS:
The force of friction is always exerted in a direction that opposes movement or potential movement between the two surfaces,
Confirmed with teacher-A,B and C.thesjarox:
[quote=\"vaidyanathan padmini\"]How about friction question from McQ.....
My dd's answer is only C as friction opposes motion...
Only the box in c is moving so it should have friction
Friction also acts on stationary objects. That's why forces have to overcome the friction before being able to move the object. Also, if there were no friction acting on an object,the object would glide across the surface, like ice, and would never stop.
Thus, A is also correct.
For B: Potential movement
For Movement
For A: non
So answer should be: B &C[/quote]
I checked yahoo answers. Friction can act on stationary objects. The inertia of the mass at rest and the coefficient of friction between the two surfaces must be overcome. -
fantasy1:
I'm not sure, but my answer was that he would observe about an equal number of fishes in each section when the water plants had been removed.HI
How abt section (B) qn
Something abt the type of colour used for photosynthesis. For Part (C) when they removed the water plants, what observation will the person see to ensure result at part (B) is correct? -
The force of friction is always exerted in a direction that opposes movement or potential movement between the two surfaces,
For B: Potential movement
For Movement
For A: non
So answer should be: B &C[/quote]
I checked yahoo answers. Friction can act on stationary objects. The inertia of the mass at rest and the coefficient of friction between the two surfaces must be overcome.[/quote]
Aslo for Yahoo answer
the frivction exists everwhere between surfaces
but if there is no other force in the horizontal direction and it rests on the horizontal surface then there is no frictional force acting on itsometimes you push a heavy object but cant move it, here although it is stationary the force which resists motion is the frictional force hence it exists and has a value exactly equal to the force you have applied on it. but the frictional force can only reach a maximum value of coeffcient of friction * normal reaction
so once your applied force exceeds this value then it will have to start moving
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