Final answer:
The frequency of small oscillations for a pivoted semicircular rod depends on its physical properties, such as the distribution of mass and moment of inertia, as well as the gravitational torque.
Step-by-step explanation:
The frequency of small oscillations of a pivoted semicircular rod can be found using the concepts of physical pendulum and simple harmonic motion. The oscillation frequency of the rod is influenced by its moment of inertia and the gravitational torque acting on it. While the formula for a simple harmonic oscillator (f) is f = 1/2π √(g/l), where g is the acceleration due to gravity and l is the length of the pendulum, this formula is typically used for a simple pendulum with a point mass.
For a physical pendulum like the semicircular rod, where the mass distribution is not concentrated at a point, the formula needs to be modified to account for the distribution of mass, which affects the moment of inertia. The exact frequency expression would be derived from the physical properties of the rod and the pivot location, which are not provided in this question.