Atrain traveling at 82.8 kilometers per hour is blowing its horn as it approaches you. the horn has a frequency of 312 hz. assume the speed of the sound is 331 m/s. what is the observed frequency of the horn?
335 hz
312 hz
292 hz
412 hz

Does heating a metal wire increase or decrease its electrical resistance? why?

What structural formula represents 4 electrons shared between two atoms?

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?