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If linear density of a rod of length 3m ...

If linear density of a rod of length 3m varies as `lamda=2+x`, then the position of the centre of mass of the rod is `P/7m`. Find the value of P.

A

`(7)/(3)m`

B

`(12)/(7)m`

C

`(10)/(7) m`

D

`(9)/(7) m`

Text Solution

Verified by Experts

The correct Answer is:
B

`lamda = (2+x) , l=3m`
`x_(CM)= (int x dm)/(int dm)= (underset(0)overset(3)int x (2+x) dx)/(underset(0)^(3)int (2+ x) dx)`
`= (underset(0)overset(3)int (2x+ x^(2)) dx)/(underset(0)^(3)int (2+x) dx)= ([x^(2) + (x^(3))/(3)]_(0)^(3))/([2x+ (x^(2))/(2)]_(0)^(3))`
`= (9+ (27)/(3))/(6+ (9)/(2))= (18)/(21) xx 2= (12)/(7)m`
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