It is driven by tempature differences within the fluid
Explanation:
Given that,
Frequency of train horn, f = 218 Hz
Speed of train, 
The speed of sound, V = 344 m/s (say)
The speed of the observed person, 
(a) When the train approaches you, the Doppler's effect gives the frequency as follows :
(b) When the train moves away from you, the Doppler's effect gives the frequency as follows :
Hence, this is the required solution.
Explanation:
7.7 m/s
1st determine you subject slade to you have a mass of 15 kg being subjected to a force of 180N
so.
180N/15kg=180(kg m)/s^2/15kg=12 ms^2
now determine how long u pushed it
d=0.5 A T^2
sutable the known values getting
2.5 m = 0.5 12 ms^2 T^2
2.5m= 0.6 ms^2 T^2
0.41667 s^2=T^2
0.645497224s=T
the velocity multiply the time by the acceleration giving
0.645497224 s 12 ms^2 =7.745966692 ms.
after rounding the 2 significant u get 7.7 ms
Acceleration = force/mass
1/4
s=ut+1/2at^2
0*4+1/2*1/4*4^2
1/2*1/4*16
1/2*4
=2
F=ma
m=300g= 0.3kg
a= -0.205i +0.700j m/s2 = <-0205, 0.7>m/s2
Thus, F = 0.3<-0.205, 0.7> N
F = <-0.0615, 0.21> N
= -0.0615i N +0.2100j N
