Answer
$64.3\ kg$
Work Step by Step
Given:
radius of spherical shell $R =1.90\ m$
moment of inertia $I =154.8\ kg. m^2$
Rotational inertia of spherical shell $I =\frac{2}{3} MR^2$
where M is the mass of the spherical shell
Therefore, we rearrange the formula to find $M$:
$M =\frac{3}{2}(\frac{I}{R^2})$
$M =\frac{3}{2}(\frac{154.8\ kg. m^2}{(1.9\ m)^2)}$
$M =64.3\ kg$
