pendulum bob的用法和樣例：
例句
- The hydrometric pendulum is sometimes used to determine flow velocities in open channels.
測流速的擺錘有時(shí)用于確定明渠中的流速。 - Huygens saw that a pendulum traversing a circular arc completed small oscillations faster than large ones.
惠更斯觀(guān)察到，若擺錘沿著(zhù)圓弧擺蕩，那麼擺動(dòng)幅度小的時(shí)候會(huì )比幅度大時(shí)振蕩得快。
