Weight- Water

[Guest]

A gallon of water contains 0.134 cu ft.

A cu. ft. contains 7.48 gallons.

A cu. ft. weighs 62.5 lbs.

Determine weight of gallon of water.


62.5 / 0.134 = 466.41

7.48 / 0.134 = 55.82

62.5 / 7.48 = 8.35

Where did I miscalculate ?

[Guest]

62.5 / 0.134 = 466.41

7.48 / 0.134 = 55.82

62.5 / 7.48 = 8.35

Where did I miscalculate ?
............what did you miscalculate..........???????

Your question asks you to find the weight of a gallon of water......

What are the above numbers you typed.....

You just typed numbers......what do ther mean.....

They need dimensions then they will mean something

the weight of a gallon has the dimension of lbs.......meaning weight

Or since it is one gallon were are talking about we could say water weight X lbs/gal.....pounds per gallon

[Guest]

This should read.......
Or since it is one gallon were are talking about we could say water weighs "X" lbs/gal..... or "X" pounds per gallon

[Guest]

62.5 lbs./ cu. ft. / 0.134 /cu. ft. = 466.41 ?

7.48 gal. / cu. ft. / 0.134 / cu. ft. = 55.82 ?

62.5 lbs. / cu. ft. / 7.48 gal. / cu. ft. = 8.35 ?

X = lbs. / gal.

?? I am more confused.

[Guest]

You didn't state the units on the right hand side of the equation....so you don't know what you were calculating....
and neither do I....................

[Guest]

A gallon of water contains 0.134 cu ft. ....so 0.134 cuft per gallon

A cu. ft. contains 7.48 gallons.

A cu. ft. weighs 62.5 lbs. so 62.5 lbs per cuft.

62.5 lbs./ cu. ft. / 0.134 /cu. ft. = 466.41 ?

I assume this means you took 62.5 lbs/cuft and divided it by 0.134 cuft/gallon.

lbs/cuft divided by cuft/gallon is same as lbs/cuft multiplied by gallons/cuft
So the units of that would be gallon.lbs per cuft squared...........
Why would you need units like that.??.....so why did you do that calculation..??

[Guest]

"Why would you need units like that.??.....so why did you do that calculation..?? "

I don't know. I wasn't sure which numbers to use.

I realize I could have looked up the conversion - I just wanted to calculate from the other information given. I am still confused.

[Guest]

The question asked you to calculate the weight of one gallon of water.
That means how many pounds per gallon. or in term of dimensional units lbs/gal.
you were told one gallon occupies 0.134 cuft, so that means 0.134 cuft per gallon
OR 0.134 cuft/gal.
And you were told 1 cuft weight 62.5 lbs. so that means 62.5 lbs per cuft OR 62.5 lbs/cuft.

So in dimension units lbs/cuft multiplied by cuft/gal......the cuft units top and bottom cancel
and you are left with lbs/gal which you want.........

So......... 62.5 x 0.134 = 8.375 lbs/gal. So 1 gallon weighs 8.375 lbs.

[Guest]

Thanks - I am not totally clear.

[Guest]

Well, you must agree ....1 cuft weighs 62.5 lbs

and 1 gallon occupies 0.134 cuft..both gallon and cuft are volume measurements
So 1 cuft is 1 divided by 0.134 = 7.46 gallons....and you were told this as well but didn't need it

So 62.5 lbs occupies 7.46 gallon = 62.5 lbs per 7.46 gallons

So 62.5 / 7.46 = 8.37 lbs per one (each) gallon = 8.37 lbs / gal

[Guest]

"Well, you must agree ....1 cuft weighs 62.5 lbs"

I agree.

Ok - I have always struggled with conversion units. I use the incorrect unit and get a wrong answer or get confused on converting.