Lucretia (a somewhat eccentric physics student) has her left ear against the concrete driveway. If someone drops a metal trash can onto the driveway about 30 m away (close enough to easily hear any sound made), will she hear one sound or two? If two, which one arrives first? Please explain your reasoning.

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..

it takes about 30 days for it to break down