4: Ultrasonic¶

Example number 4.1, Page number 84¶

In [1]:
#importing modules
import math
from __future__ import division

#Variable declaration
V1=343;     #velocity of air(m/s)
V2=1372;    #velocity f water(m/s)
dt=3;       #time difference(s)

#Calculation
S=((V1*V2)*(dt))/(V2-V1);     #distance between two ships(m)

#Result
print "distance between two ships is",S,"m"

distance between two ships is 1372.0 m


Example number 4.2, Page number 84¶

In [3]:
#importing modules
import math
from __future__ import division

#Variable declaration
V=1700;     #velocity of sound(m/s)
t=0.65;     #time(s)
n=0.07*10**6;     #frequency of source(Hz)

#Calculation
d=(V*t)/2;      #depth of sea(m)
lamda=V/n;      #wavelength of pulse(m)

#Result
print "depth of sea is",d,"m"
print "wavelength of pulse is",round(lamda,4),"m"

depth of sea is 552.5 m
wavelength of pulse is 0.0243 m


Example number 4.3, Page number 84¶

In [8]:
#importing modules
import math
from __future__ import division

#Variable declaration
P=1;
l=40*10**-3;    #length of pure rod(m)
E=115*10**9;    #Young's modulus(N/m**2)
D=7.25*10**3;   #density of pure iron(kg/m**3)

#Calculation
n=(P/(2*l))*math.sqrt(E/D);    #natural frequency of pure rod(Hz)

#Result
print "natural frequency of pure rod is",round(n/10**3,1),"kHz"
print "answer given in the book is wrong"
print "frequency of rod is more than audible range, rod can be used in magnetostriction oscillator"

natural frequency of pure rod is 49.8 kHz
answer given in the book is wrong
frequency of rod is more than audible range, rod can be used in magnetostriction oscillator