Timekeeping – identifying a pendulum by its beat A pendulum that makes one beat (one complete oscillation to and fro) per second is commonly called what?

Introduction / Context:
Classical clocks used pendulums whose period is tied to their length. One special case—the second’s pendulum—has a period convenient for timekeeping. This question asks for the standard name of a pendulum with one oscillation per second.

Given Data / Assumptions:

• “One beat per second” interpreted as one complete to-and-fro oscillation in 2 seconds for traditional terminology (one beat often half-period; in horology, a second’s pendulum has period T = 2 s, giving one swing per second).
• Small-angle approximation applies: T ≈ 2π√(L/g).
• g ≈ 9.81 m/s^2 near Earth’s surface.

Concept / Approach:
A second’s pendulum is defined to have period T = 2 s. With the small-angle formula T = 2π√(L/g), this sets a standard length used historically to regulate clocks.

Step-by-Step Solution:

Verification / Alternative check:
Clocks regulated by such pendulums tick once per second because each half swing lasts approximately 1 s, matching practical timekeeping.

Why Other Options Are Wrong:

• simple pendulum: general idealized model, not a specific period.
• compound pendulum and torsional pendulum: other physical realizations; period depends on different parameters.

Common Pitfalls:
Confusing “beat” with “period”. In horology, a beat commonly refers to a half-swing; a second’s pendulum has one beat per second and a full period of two seconds.

Final Answer:
second's pendulum