Q&A - PSLE Science

[Nebbermind]

tianzhu:

Hi chrisu


This link may help to explain why (2) is correct for Q1.

In elastic collision, the total system momentum and total kinetic energy is conserved.

Please refer to this link.

http://www.physicsclassroom.com/mmedia/momentum/trece.cfm

Best wishes

actually, it's a bit chim for psle. remember we only learn something similar (coefficient of restitution) in 'A'.

[Nebbermind]

chrisu:

The rest are from Longman My Weekly Companion Science 5/6 Book B;
Q2. Book answer is (1) which is C only. Wonder if a stronger force will cause the Marble T to move faster too? But here I think we can't tell whether it will be faster or slower, just that there will be a change in speed.
http://img.photobucket.com/albums/v160/guppiesonli/Misc/F2.jpg\">
Thank you.

Since energy is introduced to change its direction, it shd be faster. but again, is this is psle level?

[P5G]

Please help.


http://i52.tinypic.com/i3gzux.gif\">

TIA.

[P5G]

Please help.


http://i56.tinypic.com/x5s28l.gif\">


TIA.

[P5G]

Please help.


http://i56.tinypic.com/34isp44.gif\">


TIA.

[P5G]

Please help.


http://i56.tinypic.com/fyzlw7.gif\">


TIA.

[P5G]

Please help.


http://i54.tinypic.com/6qebm8.gif\">


TIA.

[htn]

need help, Rosyth preliminary 2010


Q22. A block of ice is put in a sealed plastic box.The box is then placed in the middle of a classroomon a hot day.

What will happen to the temperature of the melting ice, the water and the air in the box after some time?


Temperature of

melting ice water air in the box

1.remains the same increases decreases
2.decreases remains the same increases
3.remains the same decreases decreases
4.increases remains the same increases

what is the ans?

TIA

[Leon Wee Onn Leon]

htn:

need help, Rosyth preliminary 2010


Q22. A block of ice is put in a sealed plastic box.The box is then placed in the middle of a classroomon a hot day.

What will happen to the temperature of the melting ice, the water and the air in the box after some time?


Temperature of

melting ice water air in the box

1.remains the same increases decreases
2.decreases remains the same increases
3.remains the same decreases decreases
4.increases remains the same increases

what is the ans?

TIA

I think the answer should be (1).

When an ice cube melts, it's temperature will still remain at 0 Degrees Celsius, only when the ice melts completely, the water from it will increase in temperature. The warm air in the container loses heat to the ice cube, thus making the air to drop in temperature. As a result, the ice gained heat and will melt.

[P5G]

Please help.


http://i55.tinypic.com/wl6oy.gif\">


TIA.