What is the number of oscillations of the weight on the spring during 20 seconds, if the oscillation frequency is 4 Hz?

Initial data: t (duration of oscillations of the load on the spring) = 20 s; ν (frequency of vibration of the weight on the spring) = 4 Hz.
Since the time and frequency of oscillations are known, the number of oscillations of the load on the spring can be determined from the formula: ν = N / t, whence N = ν * t.
Let’s calculate: N = 4 * 20 = 80 vibrations.
Answer: In 20 seconds, the weight on the spring will make 80 complete vibrations.