Whats the measure of how much energy a sound wave carries, the loudness of a sound?

Rank the automobiles based on the magnitude of the force needed to stop them, from largest to smallest.2000 kg car going 5m/s500 kg car going 20 m/s1000 kg car going20m/s500 kg car going10m/s1000 kg car going10/s4000 kg car going 5m/s 0 0 603

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?

Why does lightning travel from clouds to the ground?