幾題物理原文題目

{1}.Because Earth"s rotation is gardually slowing,thelength of each day increases : The day at the end of 1.0cen-tury is 1.0ms longer than the day at the start of the century. In 20 centuries,what is total of the daily

increases in time.

{2}.Gold,which has a density of 19.32g/cm3次方,is the most ductile metal and can be pressed into a thin leaf or drawn out into a long fiber .(a)

If a sample of gold,with a mass of 27.63g,is pressed into a leaf of 1.000umthickness,what is the area of the leaf? (b)If,instead,the gold

is drawn out into a cylindrical fiber of radius 2.500um,what is the

length of the fiber

{3}.Iron has a density of 7.857g/cm^3,and the mass of an iron atom is 9.27*10的-26次方kg.If the atoms are spherical and tightly packed,(a)

what is the volume of an iron atom and (b)what is the distance between the centers of adjacents atoms?

Update:

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1) 因為地球自轉越來越慢, 每天的長度在增加: 每一個世紀的最後一天比第一天長千分之一秒. 請問20個世紀以來, 請問每天的長度總共增加了多少?

20 x 0.001 = 0.02 (20ms或是 0.02 second)

2) 黃金的比重為19.32 公克/立方公分, 它是延展性最好的金屬, 它可以被壓成金箔或是拉成纖維.

a) 一塊質重為27.63克的金子, 壓成厚度1微米的金箔, 請問金箔的面積是多少?

b) 如果拉成半徑2.500微米的圓形纖維, 請問纖維長度是多少?

a)

27.63 / 19.32 = 1.4301242 (立方公分) ---->這塊金子的總體積

1 um = 0.0001 cm

1.4301242 / 0.0001 = 14301.242 平方公分

b)

0.00025 x 0.00025 x 3.14 = 0.0000001963 平方公分(纖維的面積)

1.4301242 / 0.0000001963= 7287257.07006369 公分

3) 鐵的比重為7.857 公克/立方公分, 一個鐵原子的質量為9.27*10的-26次方公斤. 假設鐵原子是球行的聚合體,

a) 請問一個鐵原子的體積?

b) 兩個鐵原子的中心距離多少?

a) 9.27*10^-26 x 1000 = 9.27 * 10^-23 (先把原子質量從公斤換算成公克)

9.27 * 10^-23 / 7.857 = 1.17984*10的-23 立方公分

b) 球體的體積是4/3 * 3.14 * r^3

1.17984*10的-23 立方公分 = 4/3 * 3.14 * r^3

r^3 = 1.17984*10的-23 / 3.14 *3/4

r (半徑）= 6.5561907 10的-24 公分

兩顆原子的中心相距為 6.5561907 * 10的-24 * 2 = 1.31123813900471 10的-23 公分

• Donny
Lv 7

{1}.Because Earth’s rotation is gradually slowing, the length of each day increases: The day at the end of 10 century is 1.0ms longer than the day at the start of the century. In 20 centuries, what is total of the daily increases in time.

(1).因地球旋轉正逐漸緩慢中，一天的長度增長：10世紀末期比初期一天較長1.0秒。

請問，在20世紀時每天總計增加多少時間為多少?

{2}.Gold, which has a density of 19.32g /cm3, is the most ductile metal and can be pressed into a thin leaf or drawn out into a long fiber .

(a)If a sample of gold, with a mass of 27.63g , is pressed into a leaf of 1.000um thickness, what is the area of the leaf?

(b)If, instead, the gold is drawn out into a cylindrical fiber of radius 2.500um, what is the length of the fiber

(2).黃金比重19.32公克/立方公分(kg/cm3)，是高延展性金屬且可壓薄成箔片或抽長成纖維。

(a).一質量為27.63公克黃金樣品輾壓成厚度1.000微米箔片，請問箔片面積為多少?

(b).反之，此黃金抽長為圓柱形半徑2.500微米纖維，請問纖維長度為多少?

{3}.Iron has a density of 7.857g /cm^3, and the mass of an iron atom is 9.27*10的-26次方kg. If the atoms are spherical and tightly packed,

(a).what is the volume of an iron atom and

(b).what is the distance between the centers of adjacent atoms?

(3).鐵比重7.857公克/立方公分(g/cm3)，一鐵原子質量為9.27*10-26次方公斤(9.2710-26kg .)。設原子為球形且緊密聚合體，請問

(a).一原子體積為多少?且

(b).鄰近二原子間中心距為多少?

Source(s): me