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A tall cylindrical container 6 cm in diameter contains some water. 9 steel spheres of diameter 4 cm are put into the water. If the all the spheres are under water and no water overflows from the container then the rise in water level is.

 Apr 8, 2017
 #1
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Note that the added volume of the spheres  =

 

(9)(4/3)pi * (radius of the spheres)^3  =

 

(9)(4/3)pi * (2cm)^3  =

 

96pi cm^3     (1)

 

So.......the added volume can be considered as a new "cylinder" with a radius of 3 cm....and we have

 

Vcylinder = pi * r^2 * h   .......subbing for the radius and setting this equal to (1), we have

 

96 pi cm^3   =  pi * (3 cm)^2 * h

 

96 cm^3  = 9cm^2 * h          divide both sides by 9 cm^2

 

(96/9)cm  = h  =  32/3 cm

 

So......the water rises 32/3 cm ≈ 10.666... cm

 

 

cool cool cool

 Apr 8, 2017
edited by CPhill  Apr 8, 2017

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