The linear mass density of a thin rod AB of length L varies from A to B as λ x = λ 0 1 + x L ,…

The linear mass density of a thin rod AB of length L varies from A to B as λx=λ01+xL, where x is the distance from A. If M is the mass of the rod then its moment of inertia about an axis passing through A and perpendicular to the rod :
  1. 512ML2
  2. 718ML2
  3. 25ML2
  4. 37ML2

Solution

dm=λ.dv

dI=dm.x2

=λ01+xL.x2dx

I=λ001x2+x3Ldx

=λ0x33+x44L0L

=λ0L33+L34

I=7λ0L312

m=0Lλdx=3λ0L2

Im=7L212×32=7L218

 I=718mL2

 

Asked in: JEE Main 2020 (06 Sep Shift 2)

Practice more Rotational Motion questions on Aicharya