# leaky sandbagt

• Jan 31st 2009, 06:30 PM
alex83
leaky sandbagt
bag of sand with original weight 144 lb..
lifted in cnst rate & leaks in cnst rate ..
it was 1/2 weight (72 lb) when lifted up to 18ft ....
how to find work done this far ....

i did set the integral from 0-18
but cant find f(x)

any help pls.:)
• Jan 31st 2009, 06:45 PM
ahawk1
Quote:

Originally Posted by alex83
bag of sand with original weight 144 lb..
lifted in cnst rate & leaks in cnst rate ..
it was 1/2 weight (72 lb) when lifted up to 18ft ....
how to find work done this far ....

i did set the integral from 0-18
but cant find f(x)

any help pls.:)

ill try and help lol.
f(o)=144 lbs, f(18)=72, therefore f(x)=144-(72/18)x. Next u take the integral of that and taking the integral from 0-18 u get 144x-2x^2 |0-18
giving u an answer of 1944 ftlbs.
im assuming u can take the intrgral by urself so i didnt explain that to much. does that answer ur question?

lol what book are u using, i had the same problem?
• Jan 31st 2009, 06:50 PM
alex83
thanks 4 ur help tha was fast
thank u yes it does help ..
i was just looking 4 [f(o)=144 lbs, f(18)=72, therefore f(x)=144-(72/18)x]
i can deal with the integral :)
thanks again
• Jan 31st 2009, 07:20 PM
alex83
book
im using THOMAS CALCULUS EARLY TRASCENDENTALS

i dont think its a great one cuz it doesnt explain alot

do u have any other book thats more helpful for calc

thnx
• Jan 31st 2009, 08:10 PM
ahawk1
Quote:

Originally Posted by alex83
im using THOMAS CALCULUS EARLY TRASCENDENTALS

i dont think its a great one cuz it doesnt explain alot

do u have any other book thats more helpful for calc

thnx

im using Calculus Early Vectors by Stewart its an alright book but i usually get help from my professors office hours but those are only like two days a week so i get on here for help lol. I understand most of what is taught to me on here.