You need to know about these quantities used in waves - what they mean, the symbols used for them and the units used to measure them. The amplitude (\(a\)) of a wave is the distance from the ...

As an airplane flies faster than the speed of sound, it "pushes" on the sound waves in front of it. But sound waves obey the speed limit—they can't travel faster than the speed of sound.

San Francisco launches its first speed enforcement cameras, targeting vehicles exceeding speed limits by 11 mph or more.