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Physics/Fluid static


Edward wrote at 2013-04-26 17:22:46
First of all convert 5 gals to ft^3 because gallons is a unit of volume.

V = 5 gal X (1 ft^3/7.48 gal) = .668 ft.^3

Now we need to know how much this volume of castor oil weighs. We know the specific weight and volume and need to know the weight.

weight = specific weight X Volume

W = (59.69 lb/ft.^3) X (.668 ft.^3) = 39.9 lb.

Now we use this weight for mercury.

You need to find the specific weight of the mercury.

specific weight of the mercury = (13.54) X (62.4 lb/ft.^3) = 844.896 lb./ft.^3

Now we need to find the volume of mercury that has the weight of the castor oil of 39.9 lb.

Now specific weight = weight / Volume, Where we have the weight that needs to equal the 5 gal which is 39.9 lb. and the specific weight of the mercury is 13.54.

v = (39.9 lb.) X (ft.^3 / 844.896 lb.) = .04722 ft.^3

now we need to convert this volume to gals by using the conversion factor.

V = (.04722 ft.^3) X ( 7.48 gal / 1 ft.^3) = .353 gal

V = .353 gal

Hopefully this helps



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Sanjeet Singh Adarsh


I can answer questions in the area of mechanics(statics & dynamics), SHM(undamped) & general questions related to automotive axles & braking to start with, as I am updating myself currently in the other areas like elctricity & magnetism. The level of questions I expect is as found in most of the pre-engineering entrance examinations & as of first year physcis courses for under-graduate students.


I have been taking private tutions to some of my college juniors for physics & maths. General physics is the main area of my interest.

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PTC R&D (India) Pvt. Ltd. (

B. Tech (Mechanical Engg) from IIT-Bombay(India), (1992-1996)

Awards and Honors
2 in Maths Olympiad conducted by IIT-Bombay in 1991.
In top ten percent in NSEP 1990.(a national level exam in general physics).

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