The spring pendulum makes 30 vibrations in 15 s. Determine the mass of the load if the spring rate is k = 175 h / m.

The oscillation period of the spring pendulum:
T = t / N, where t is the time during which N oscillations of the spring pendulum occurred (t = 15 s), N is the number of oscillations of the spring pendulum (N = 30).
T = N / t = 15/30 = 0.5 s.
Т = 2Π * sqrt (m / k), where m is the mass of the load (kg), k is the stiffness of the pendulum spring (coefficient of elasticity, k = 175 N / m).
sqrt (m / k) = T / 2Π.
m / k = (T / 2Π) ².
m = k * (T / 2Π) ² = 175 * (0.5 / 2 * 3.14) ² = 1.11 kg.
Answer: The weight of the load is 1.11 kg.