mistake where???????

Dont know where I am wrong.......
I solved this question by 2 diff methods and am getting answers diff.....plzz tel my mistake
Q A sphere of 5 kg specific gravity 2 is completely submerged into water.Find radius of sphere

method 1
Volome of sphere=mass /density =5/(2*103)=4/3 πr3
=>r=√(15*10-3/8π )

method2
Upthrust=Gravity
=>Vρwg=mg
=>(4/3 πr3)(103)=5
=>r=√(15*10-3/4π)

where is the mistake?????????[7][7][7]

5 Answers

1
chinmay ·

maybe because they haven't given that it is in equlibrium or something ,u can't use method 2,
what if the sphere lies at the bottom ??

3
iitimcomin ·

yaar upthrus = weight only when its just floatin or sp. gravity is 1!!!!!!!!!!!!!!!!
so method 2 is rong!!!!!!!!!!!!!![2]................................

method 1 luks all right just make sure ur units ar right and ull get the answer!!!!!

33
Abhishek Priyam ·

same post..

http://targetiit.com/iit_jee_forum/posts/mistake_where_2582.html

11
Anirudh Narayanan ·

eureka must have double clicked on the "add topic" button.....happens a lot of times [4]

24
eureka123 ·

yaa its double post...................priyam and ashish already helped me there.........but thanx again.[1][1]

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