Friday, February 5, 2010

Submerge The Ball

Suppose you have a very large steel box that is open topped.It measures 50 feet x 50 feet x 50 feet.Inside this box is a steel ball-bearing that has a diameter of 42 feet.If you started filling this box with mercury,how many cubic feet would you have to pour in, in order to completely submerge the ball?

19 Comments:

Anonymous Anonymous said...

8622.8417404197 cu feet
(4/3)pi(21)^3=116377.1582595803
50^3=125000
125000-116377.1582595803=8622.8417404197

February 5, 2010 4:41 PM  
Blogger Knightmare said...

Anonymous...that isn't the answer i have

February 5, 2010 4:44 PM  
Anonymous Anonymous said...

My bad ( iPod calculator is annoying @ times)
actuall instead of 116377...., it's 38792.38609(according to a graphing calculator)
so it's 125000-38792.38609=86207.61931

February 5, 2010 4:52 PM  
Anonymous Anonymous said...

That was my dad sry

February 5, 2010 4:53 PM  
Blogger Zaux said...

This post has been removed by the author.

February 5, 2010 4:55 PM  
Blogger Chris said...

The ball bearing would float (unless you fixed it down), so it can't be done.

February 5, 2010 4:58 PM  
Blogger Zaux said...

66,207.53 cu ft.

doint htis while on the phone ... probably wrong

February 5, 2010 4:58 PM  
Blogger Zaux said...

yea ...didn't consider it floating

February 5, 2010 5:00 PM  
Blogger Knightmare said...

Chris...you got it(but too fast-i wanted to mess with Anonymous some more) :{

February 5, 2010 5:03 PM  
Anonymous Anonymous said...

Yeah that's a bit too advanced for me

February 5, 2010 5:05 PM  
Blogger Zaux said...

if it did not float ...

Anonymous used the entire 50ft height of the box and to cover the non-floating ball ...would only need 42ft. in height.

February 5, 2010 5:07 PM  
Blogger Chris said...

Sorry Knightmare.

If it didn't float, then it would be 66207.6139 approx.

February 5, 2010 5:13 PM  
Blogger Chris said...

I reckon that's the best part $10,000,000 worth of mercury.

February 5, 2010 5:36 PM  
Blogger Knightmare said...

i get the stuff at discount

February 5, 2010 5:49 PM  
Blogger RiDiM said...

According to me the answer comes out to be 92652 cubic feet.

Required volume =
= 50X50X42 - 4/3X21X21X21
= 42 (2500 - 294)
= 92652.

February 6, 2010 1:23 AM  
Blogger RiDiM said...

sorry, missed the PI in the post..

Required volume =
= 50X50X42 - (4/3)X(22/7)X21X21X21
= 42 (2500 - 924)
= 66192

Thats the answer!

February 6, 2010 1:48 AM  
Blogger Chris said...

Hi RiDiM. If you'd used π instead of 22/7, you'd have got 66207.6139...

February 6, 2010 10:52 AM  
Anonymous Anonymous said...

This is a classic trick question, Chris got it right, stell floats in mercury so it's not possible.

February 6, 2010 2:43 PM  
Anonymous Anonymous said...

oops meant STEEL floats in mercury :)

February 6, 2010 2:44 PM  

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