Q&A - PSLE Science

[P5G]

Please help.


http://i55.tinypic.com/v62qet.gif\">

TIA.

[P5G]

Pease help.


http://i52.tinypic.com/2yuyrh5.gif\">
http://i51.tinypic.com/11w6hya.gif\">

TIA.

[P5G]

Please help.


http://i53.tinypic.com/nben88.gif\">

TIA.

[Cockroach]

P5G:

Please help.


http://i56.tinypic.com/29nbdsp.gif\">

TIA.

The smooth slippery surface reduces friction and causes the insect to slip into the liquid. The downward pointing hairs prevent the insect from crawling up to escape.

[Cockroach]

P5G:

Pease help.


http://i52.tinypic.com/2yuyrh5.gif\">
http://i51.tinypic.com/11w6hya.gif\">

TIA.

a) A,F
A
b) Gravity and friction
c) Kinetic energy -> heat+ sound

[atutor2001]

Hi Pita, below are my comments.

[quote].....Therefore, air outside the flask in the plastic tube does not have to enter the flask to fill up the space. [/quote]When the flask expanded, the air in the plastic tube must \"spread out\" into the flask because the tube is connected to the flask. With nothing separating the air in the tube and the flask, these 2 volumes of the air must be considered as 1 whole \"body\".
[quote]Thus, equal forces from both flasks in this case are pushing the water droplet, so it should not move at all [/quote]Since the air in the tube must also \"spread into the flask\" the pressure (force) acting on this side of the ink drop will decrease causing the ink to move towards the expanded flask. As the ink moves, the volume on the side of the expanded flask decreases causing the pressure to increase. At the same time, the the volume of the tube on the other side of the ink drop increases, causing the pressure to decrease. (Therefore, the movement of the ink causes opposite effect to the pressure on the 2 sides) The ink will stop moving when the pressure (force) on both sides of the ink becomes equal again.

[Pita]

Hi atutor2001,


Thank you so, so much for your explanations, really appreciate your help!

[atutor2001]

P5G:

Please help.



http://i54.tinypic.com/dlqgxs.gif\">


TIA.

This looks like a math question.

4000m - 1000m = 3000m
6 degree - 0 degree = 6 degree

6 degree -> 3000m
1 degree -> 3000/6 = 500m

1000m + 500m = 1500m

I will put 1501m (amended) as the answer because at 1500m the temp is 5 degree but the fish needs a temperature of \"less than 5 degree\".

(quite a bad question)

[P5G]

Please help.


http://i51.tinypic.com/w7jx1l.gif\">


TIA.

[P5G]

Cockroach:

P5G:

Pease help.


http://i52.tinypic.com/2yuyrh5.gif\">
http://i51.tinypic.com/11w6hya.gif\">

TIA.

a) A,F
A
b) Gravity and friction
c) Kinetic energy -> heat+ sound

Hi,

Thanks for your answers.

My original answers were the same as yours, but I think they are not correct (see my doubts below) and I could not think of any better answers.

My doubts:
For a) if Kinetic energy is 0, then the car will not have hit the bumper.
[When we drop something from a height, the kinetic energy is the highest when it hits the floor.]

For c), it is funny to me that energy of car hitting the bumper is heat energy and sound energy.