The harmonic equation is x = 0.1 cos (20pt + p / 3). Find the oscillation period.

The equation of harmonic vibrations of a material point can be represented as a function:
x = A * cos (ω * t + φ0), where A is the amplitude of the oscillations, ω is the cyclic frequency, t is a given moment in time, φ0 is the initial phase of the oscillations.
From the initial equation: x = 0.1 * cos (20Pt + P / 3), it follows that the cyclic frequency ω = 20Π.
We find the oscillation period from the formula:
ω = 2Π / Т, where Т is the oscillation period.
T = 2Π / ω = 2Π / 20Π = 2/20 = 0.1 s.
Answer: D) The oscillation period is 0.1 s.