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

Data: n (number of pendulum oscillations) = 30 oscillations; t (oscillation duration) = 15 s; k (spring rate of the pendulum) = 175 N / m.

To determine the mass of the load attached to the pendulum, we use the equality: T = t / n = 2 * Π * √ (m / k); m / k = t ^ 2 / (4 * Π ^ 2 * n ^ 2) and m = t ^ 2 * k / (4 * Π ^ 2 * n ^ 2).

Calculation: m = 15 ^ 2 * 175 / (4 * 3.14 ^ 2 * 30 ^ 2) = 1.109 kg.

Answer: A weight of 1.109 kg was suspended from a spring pendulum.