The behavior of a sound wave is affected by the density of the medium, the temperature of the medium and the pressure of the medium if it is a gas. Motion of the medium independent of the sound wave may also affect the way sound propagates.
Yes, you may check-in for your Delta Air Lines (DL) flight with your mobile device starting 24 hours and ending 60 minutes before the scheduled departure time (depending on your departure city and destination) to receive a mobile boarding pass on your mobile device.
Youâll get your free checked bag automatically when you check-in, as long as your Delta frequent flyer number is on your reservation. No Need to Wait for a Statement Credit. Youâll Get a Free Bag Automatically! So you donât have to pay and then wait for a credit.