Sonic booms are measured in poundsper square foot of overpressure.
音爆是以每平方英尺的超压磅数来测量的。
2
Aluminum, which weighs about 169 poundsper cubic foot, could theoretically be substituted for copper.
铝,重约169磅每立方英尺,理论上可以替代铜。
3
The change in air pressure associated with a sonic boom is only a few poundsper square foot — about the same pressure change experienced riding an elevator down two or three floors.