Q&A - PSLE Science

[P5G]

Please help.


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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.

[chrisu]

Thanks Tianzhu. This really chim for P6. How to tell its elastic colision and not inelastic collision since it's not mentioned in question.

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

[htn]

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.

Leon Wee Onn Leon

Thanks

[Nebbermind]

For the melting ice problem, shdn’t it be :


remain, remain & decrease? (since it stated ‘melting ice’, so water must be ‘0’)