Answer:
(a) the observed frequency is 200 Hz
(b) the observed frequency is 188 Hz.
Explanation:
speed of the truck, Vs = 27 m/s
frequency of the truck as it approaches, Fs = 185 Hz
(a) Apply Doppler effect to determine the frequency you will hear.
As the truck approaches you, the observed frequency will be higher than the source frequency because of decrease in distance.
![F_s = F_o [\frac{V}{V_S + V} ]](https://tex.z-dn.net/?f=F_s%20%3D%20F_o%20%5B%5Cfrac%7BV%7D%7BV_S%20%2B%20V%7D%20%5D)
Where;
Fo is the observed frequency which is the frequency you will hear.
V is speed of sound in air

(b) Apply the following formula for a moving observer and a moving source;
](https://tex.z-dn.net/?f=F_o%20%3D%20F_s%5B%5Cfrac%7BV-V_o%7D%7BV%7D%20%5D%28%5Cfrac%7BV%7D%7BV-V_S%7D%20%29)
The observed frequency is negative since you are driving away from the truck and the source frequency is also negative since it is driving towards you.
\\\\F_o = 185[\frac{340-22}{340} ](\frac{340}{340-27} )\\\\F_o = 185(0.9353)(1.0863)\\\\F_o = 188 \ Hz](https://tex.z-dn.net/?f=F_o%20%3D%20F_s%5B%5Cfrac%7BV-V_o%7D%7BV%7D%20%5D%28%5Cfrac%7BV%7D%7BV-V_S%7D%20%29%5C%5C%5C%5CF_o%20%3D%20185%5B%5Cfrac%7B340-22%7D%7B340%7D%20%5D%28%5Cfrac%7B340%7D%7B340-27%7D%20%29%5C%5C%5C%5CF_o%20%3D%20185%280.9353%29%281.0863%29%5C%5C%5C%5CF_o%20%3D%20188%20%5C%20Hz)
In transversal wave particles do not oscillate along the line of the wave propagation but oscillate up and down about their mean position as the wave travels.thus transverse wave is the one in which individual particles of the medium move about their mean position in a direction perpendicular to the direction of wave propprgation.
In longitutional waves the individual particles of the medium move in the direction parallel to the direction of the propprgation of the disturbance. The particles do not move from one place to another but the simply oscillate back and forth about their position of the rest.
HOPE IT HELPS.