A solid has a unifrom cross section of area 45cm^2 and height 50cm.If the solid is melt and recast into of side length 2cm,how many cubes can be made?
The length and width of a swimming pool are 50m and 20m respectively.The depyh of water is 1m at the shallow end and 2m at the deep end. Find the volume of water that the swimming pool can contain.
The figure shows a container with a unifrom cross section in the shape of a triangle.The area of the unifrom cross section is 24cm^2.There is some water in the container.If a rectangular block of length 3cm,width 2cm and height 2cm are totally immersed in water and there is no overflow of water,find the rise in water level.
Maths!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2008-03-27 12:47 am
回答 (2)
2008-03-28 3:21 am
✔ 最佳答案
(1)The volume of the solid = 45*50 cm^3 = 2250 cm^3
The volume of a cube = 2*2*2 cm^3 = 8 cm^3
The number of cubes can be made
＜＝ the volume of the solid / the volume of a cube
= 2250/8 = 281.25
∴ 281 cubes can be made.
(2) The volume of the swimming pool
= the area of the trapezoid wall * width
= (shallow end deep end) * length / 2 * width
= (1 2)*50/2*20
= 1500 m^3
(3)
The volume of the rectangular block = 3*2*2 cm^3 = 12 cm^3
The rise in water level
= the volume of the rectangular block / the area of the container
= 12/24 cm
= 0.5 cm
2008-03-27 1:34 am
a) 45x50/(2x2x2)=281.25>>281 cubes can be made.
b) (1+2)*50/2*20 =1500 m^3 =1500000L
c)3x2x2/24=0.5cm
b) (1+2)*50/2*20 =1500 m^3 =1500000L
c)3x2x2/24=0.5cm
參考: MYSELF
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