關於mass同weight一問

Question

A : The weight of an object at a particular place is proportional to its mass.

B : Both the mass and the weight of an object very slightly at different place on the earth

以上既statements,,,邊個係岩..邊個係錯..

俾埋原因..點解個個岩,,點解另外個個錯~

萬分感激!!!!

Answer 1

Favorite Answer

A is correct. B is incorrect.

For A, weight = mass X acceleration due to gravity

i.e. W = mg

where g is the acceleration due to gravity (gravitationalfield strength), in which it can be treated as a constant.

So, weight of an object at a particular place isproportional to its mass.

For B, mass is a property of matter. That is it does not varyin different places. It should be the same at all places.

Weight is a property of space. W = mg, The weight depends onthe magnitude of g, which can be varied. So it varies very slightly atdifferent places.

Source(s): Myself~~~

Answer 2

you may ask,

why the manitude of g can be varied? (statement2)

因為地球不停地轉動，會產生一種自轉離心力，因此物體所受重力的大小，等於地心引力和自轉慣性離心力的合力，應當是地心引力減去自轉慣性離心力在垂直方向的分量。因為地球是兩極稍扁的橢球體，越近赤道，地面與地心的距離越遠，地心引力也就越小。另一方面，越近赤道，物體隨地球自轉產生的自轉離心力卻越來越大，所以越近赤道，物體實際所受重力就越小

參考資料：十萬個為甚麼—物理篇1(p.2)

上述資料涉及中六課程，不過這本書是不分年級的-.-