劍橋詞典a large increase in the force opposing a moving object as its speed reaches the speed at which sound travels 聲障，音障（指飛行物的速度達(dá)到音速時(shí)所産生的氣動(dòng)阻力急劇增大） There is usually a sonic boom when an aircraft breaks the sound barrier . 飛機(jī)沖破聲障時(shí)，通常會(huì)産生音爆。 返回 the sound barrier