Question

The radius of gyration of a body about an axis at a distance 4cm from its centre of mass is 5cm. Radius of gyration about a parallel axis passing through its centre of mass is

Answer 1

Dear Student ,
I = m(r+x)2 where I is the moment of inertia and m is the mass of the body.
here r+x = k where k is the radius of gyration , r is the radius of the object and x is the perpendicular distance of axis from Centre Of Mass.
So , Radius of Gyration about a parallel axis passing through its centre of mass = r ( as x is now zero ).
So r = k
​Thus , new radius of gyration , k = r = 10cm - 6cm = 4cm

Answer 2

Hello everyone ,

This problem is from Radius of gyrations.

Answer:

mrgCM2+mr2=mrg2. - Formula

rgCM2+r2=rg2

rgCM2+4×4=5×5

rgCM=3cms

Hope this would help you