試題詳解

13.A thin rod whose length L is 10cm and whose mass m is 100g, suspended at its midpoint from a long wire. Its period T_a of angular SHM (Simple Harmonic Motion) is measured to be 2.50 s. An irregularly shaped object is then hung from the same wire and its period T_b is found to be 5.0s. What is the rotational inertia of the irregular object about its suspension axis? (The rotational inertia for a rod is  mL²  )
(A)
(B)
(C)
(D)
(E)