Question

HELP PLeASE?

1. When the energy of a sound wave is transferred to a particle of a medium and causes it to vibrate and generate heat, the sound wave is _____

A) reflected
B) refracted
C) absorbed
D) transmitted

2. The pitch of the siren of a moving fire truck changes from high to low as the fire truck passes by. What property of a sound wave changes as the fire truck goes by?

A) amplitude
B) density
C) temperature
D) frequency