How many vibrations does a metal ball make during 20 seconds, suspended on a thread 1.6 m long?

To calculate the required number of vibrations of the taken metal ball on the thread, we use the equality: 2 * Π * √ (l / g) = T = t / n, whence we express: n = t / (2 * Π * √ (l / g)) …

Constants and variables: t – oscillation time (t = 20 s); l is the length of the thread (l = 1.6 m); g – acceleration due to gravity (g ≈ 10 m / s).

Let’s calculate: n = t / (2 * Π * √ (l / g)) = 20 / (2 * 3.14 * √ (1.6 / 10)) ≈ 8 oscillations.

Answer: A taken metal ball will make 8 vibrations in 20 seconds.