For a science experiment, you would like to use the Doppler effect to double the perceived frequency of a harmonica, from the 261.7-Hz tone (middle C) that it emits, to 523.3 Hz (C_5 note). Which strategy will accomplish your goal more easily: move the observer move the harmonica Calculate the speed the harmonica must have in order for a stationary observer to hear 523.3 Hz. Express your answer to three significant figures and include appropriate units. Calculate the speed an observer must have in order to perceive a 523.3-Hz sound from a stationary harmonica that emits sound at 261.7 Hz. Express your answer to three significant figures and include appropriate units.

the answer would most likely be c, because if it's a comical piece of information, it may likely not be true, if it's a site that allows anybody to edit the content, it could mean a five year old is typing the info, and if it's a tv show produced by a celeb, it may have a biased opinion.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s