Question

The rotational inertia of a disk about its axis is 0.70kgm2. When a 2kg mass is added to its rim ,0.40m what will be its rotational inertia?

Answer 1

The moment of inertia is `=1.02kgm^2`

Explanation:

The moment of inertia of the disc about the axis `O` is

`I_O=0.7kgm^2`

The moment of inertia of the mass is

`I_m=mr^2=2*0.4^2=0.32kgm^2`

The total moment of inertia is

`I=I_O+I_m=0.7+0.32=1.02kgm^2`