A uniform solid sphere is rotated about two parallel axes: one that passes through…
PHYSICS · Single correct · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion
Problem
A uniform solid sphere is rotated about two parallel axes: one that passes through its center of mass and a second that is 0.10m above the first. Which of the following best explains why the rotational inertia about the second axis is greater than that about the central axis?
(a) The total mass of the sphere effectively increases when the axis is moved.
(b) Because the new axis is closer to the surface, the radius in I=52MR2 becomes (R+0.10m), so the rotational inertia increases.
(c) Each mass element is, on average, farther from the second axis, increasing the sum of mr2 terms.
(d) The torque required to start rotation is smaller about an off-center axis, indicating a larger rotational inertia.