Rotational Motion Question 177

Question: Particles of masses m, 2m, 3m,………….nm grams are placed on the same line at distances l,2l,3l,.nl cm from a fixed point. The distance of centre of mass of the particles from the fixed point in centimeters is

Options:

A) (2n+1)l3

B) 1n+1

C) n(n2+1)l2

D) 2ln(n2+1)

Show Answer

Answer:

Correct Answer: A

Solution:

[a]

xcm=m×+2m×2+3m×3++nm×nm+2m+3m+..+nm

=(1+4+9+..+n2)1+2+..+n

=n(n+1)(2n+1)/6n(n+1)/2=(2n+1)3



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