Asound wave moves from a medium where particles of matter are closely packed to a medium where particles are farther apart. how do you expect the sound to travel differently?

the wave will move faster, increasing its amplitude.

there will be not change in the wave's travel.

the sound will slow down, changing its speed.

the wavelength will change along with frequency.

the answer is the first one "The wave will move faster, increasing its amplitude."

co2reflects heat radiation back to earth buning coal and oil emits co2 globe warms

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.