16-09-09 Find the center of mass of this object....

Part 1

here the radius side of the successive square is half of the original one... (The whole thing goes to infinity)

Side of the Largest square is 1.

Part 2

Find the CM of this system...
Here you successively add the same kind of cut squares.. Infinitely many times

First take a square of side one. Remove 1/4th of ti.. then add a square of 1/4th the side of original side and repeat the same thing...

Take the origin as the lower most left point of the bottom square...

16 Answers

106
Asish Mahapatra ·

sir where do we take the origin?

62
Lokesh Verma ·

Take it whereever you want...

for instance the left bottom most point...

106
Asish Mahapatra ·

sir:
here the radius of the successive square is half of the original one... ??

62
Lokesh Verma ·

oops i meant side :P

62
Lokesh Verma ·

Asish think of a simpler method?

1
Philip Calvert ·

R =\frac{ M + \frac{M}{3}(1+R)}{4M/3}

R gives us the x as well as y coordinate of COM

M is mass of the first block

I suppose there is a small error but this was the best method i could think of

62
Lokesh Verma ·

No Philitp there is an error

1
Philip Calvert ·

Yes I realized as much...

the answer to part I

(57,57)

to part II

(37,37)
____________________________________

for part I

I used

R =\frac{ M.(1/2) + \frac{M}{3}(1+R/2)}{4M/3}
symbols have the same meaning as in #9

similarly for part II

1
Philip Calvert ·

Someone please confirm the answer

PS : I have assumed uniform density

62
Lokesh Verma ·

Yes philip that is the way :)

62
Lokesh Verma ·

I have not verified the 2nd part... but the 1st one is correct...

can someone post the exact expressoin for the 2nd part?

1
Philip Calvert ·

I just did not want to end this thread here so I left the expression for part II

however here it is

R\, =\, \frac{3M(\frac{5}{12})+\frac{M}{5}(\frac{R}{4}+\frac{1}{2})}{\frac{16M}{5}}

here 3M is the mass of the first block
taken side of largest block as 1

62
Lokesh Verma ·

Great :)

1
Grandmaster ·

one doubt sir.....is the mass of each square same or is the material same!!!!!

62
Lokesh Verma ·

The material is the same..

1
RAY ·

wht the way??

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