Asonic boom is caused by
a sound-producing object moving toward an observer

a sound-producing object overtaking it’s own sound waves

a sound-producing object moving away from an observer

a sound-producing object traveling just slower than its own sound waves

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?