Introduction To Special Relativity And Space Science (By S.P. Singh)

CHAPTER NUMBER 8 : OUR SOLAR SYSTEM

EXAMPLE NUMBER 8.4a : (Page Number 300)

In [146]:
import math
   #Given that
t1 = 1    # time period of satellite s1 in hours
t2 = 8    # time period of satellite s2 in hour
r1 = 1.2e4    # radius of orbit of satellite s1 in km
print "Standard formula r2/r1 = (t2/t1)**(2/3)"
r2 = r1 * (t2/t1)**(2/3)    # calculation of radius of orbit of satellite s2 in km
v1 = 2 * pi * r1 / t1     # calculation of speed of satellite s1 in km/h
v2 = 2 * pi * r2 / t2     # calculation of speed of satellite s2 in km/h
del_v = v2 - v1    # calculation of relative speed of satellites in km/h

print "   Relative speed of satellite s2 wrt satellite s1 is ",del_v," km/h."
Standard formula r2/r1 = (t2/t1)**(2/3)
   Relative speed of satellite s2 wrt satellite s1 is  -65940.0  km/h.

EXAMPLE NUMBER 8.5 : (Page Number 300)

In [152]:
import math
   #Given that
h = 2620    # distance of satellite from surface of Earth in km
R_e = 6400    # radius of Earth in km
M_e = 6e24    # mass of Earth in kg
G = 6.67e-11    # universal gravitational constant 
print "Standard formula used  \t v_o = math.sqrt(G*M_e/r)   "
print "  \t T = 2 * pi * r / v_o   "
r = R_e + h
v_o = math.sqrt(G * M_e / (r * 1e3))
T = 2 * pi * r*1000 / (v_o*3600)
print "  Orbital velocity of satellite is ",round(v_o / 1000,4)," km/s   period of revolution is ",round(T,4)," h."
Standard formula used  	 v_o = math.sqrt(G*M_e/r)   
  	 T = 2 * pi * r / v_o   
  Orbital velocity of satellite is  6.6609  km/s   period of revolution is  2.3623  h.

EXAMPLE NUMBER 8.6 : (Page Number 301)

In [154]:
import math
   #Given that
h = 3e5    # distance of satellite from surface of Earth in m
R_e = 6.38e6    # radius of Earth in km
M_e = 6e24    # mass of Earth in kg
g = 9.8    # gravitational acceleration in m/s2 
print "Standard formula used v_o = math.sqrt(G*M_e/r)   "
print "Standard formula used T = 2 * pi * r / v_o   "
r = R_e + h   # calculation of effective distance between Earth and satellite

G = g * R_e**2 / M_e   # calculation of gravitational constant 
v_o = math.sqrt(G * M_e / r) / 1000   # calculation of orbital velocity of satellite
T = 2 * pi * r / (v_o * 1000) / 3.6e3    # calculation of period of revolution of satellite

print "  Orbital velocity of satellite is ",round(v_o,4)," km/s    period of revolution is ",round(T,4)," h."
Standard formula used v_o = math.sqrt(G*M_e/r)   
Standard formula used T = 2 * pi * r / v_o   
  Orbital velocity of satellite is  7.7276  km/s    period of revolution is  1.508  h.

EXAMPLE NUMBER 8.7 : (Page Number 301)

In [156]:
import math
   #Given that
t = 27.3    # period of lunar orbit around Earth in days
r = 3.9e5    # distance of satellite from  Earth in km
G = 6.67e-11    # universal gravitational constant 
print "Standard formula used   T = 2 * pi * math.sqrt ((r**3)/G*M_e)   "
T = t * 24 * 60 * 60   # calculation of time in seconds
M_e = 4 * pi**2 * (r * 1000)**3 / (G * T**2)    # calculation of mass of Earth
print "  Estimated mass of Earth is ",M_e," kg."
Standard formula used   T = 2 * pi * math.sqrt ((r**3)/G*M_e)   
  Estimated mass of Earth is  6.30426551023e+24  kg.

EXAMPLE NUMBER 8.8 : (Page Number 302)

In [157]:
import math
   #Given that
t = 1    # period of  Earth's revolution around Sun in years
r = 1.5e8    # distance between Sun and Earth in km
G = 6.67e-11    # Universal gravitational constant
print "Standard formula used T = 2 * pi * math.sqrt ((r**3)/G*M_e)   "
T = t * 24 * 60 * 60 *356   # calculation of time period in seconds
M_s = 4 * pi**2 * (r * 1000)**3 / (G * T**2)    # calculation of mass of Sun
print "  Estimated mass of Sun is ",M_s," kg."
Standard formula used T = 2 * pi * math.sqrt ((r**3)/G*M_e)   
  Estimated mass of Sun is  2.10930678583e+30  kg.

EXAMPLE NUMBER 8.9 : (Page Number 302)

In [158]:
import math
   #Given that
R_e = 6.4e6    # radius of Earth in km
M_e = 6e24    # mass of Earth in kg
G = 6.67e-11    # universal gravitational constant
u = 6e3    # initial speed of rocket in m/s
print "Standard formula used U_f - U_i = 1/2 * m *(u**2 - v**2)  "
h = ((R_e * 1e3)**2 * u**2) / (2 * G * M_e - R_e * u**2) / 1000       # calculation of Height reached by rocket before returning to Earth

print "  Height reached by rocket before returning is ",h," km."
Standard formula used U_f - U_i = 1/2 * m *(u**2 - v**2)  
  Height reached by rocket before returning is  2586947368.42  km.

EXAMPLE NUMBER 8.10 : (Page Number 303)

In [160]:
import math
   #Given that
R_e = 6.4e6    # radius of Earth in km
M_e = 6e24    # mass of Earth in kg
G = 6.67e-11    # universal gravitational constant
print "Standard formula used U_f - U_i = 1/2 * m *(u**2 - v**2)  "
h = 10 * R_e
v = math.sqrt (2 *h * G * M_e / (R_e * h))     # calculation of velocity required by mass to reach given height
print "  Velocity required by mass is ",round(v,4)," m/s."
Standard formula used U_f - U_i = 1/2 * m *(u**2 - v**2)  
  Velocity required by mass is  11183.1346  m/s.

EXAMPLE NUMBER 8.11 : (Page Number 304)

In [161]:
import math
   #Given that
r1 = 1e12    # distance of first planet from Sun in m
r2 = 1e13    #distance of first planet from Sun in m 
print "Standard formula used T**2 = k* r**3"
print "  Standers formula used v = 2 * pi * r / T"
r_ratio = r1 / r2    # r_ratio is ratio of distances from Sun
T_ratio = r_ratio**(3/2)    #calculation of Ratio of time period
v_ratio = r_ratio / T_ratio    # calculation of ratio of speed

print "   Ratio of time period is ",T_ratio," and ratio of speed is ",v_ratio," ."
Standard formula used T**2 = k* r**3
  Standers formula used v = 2 * pi * r / T
   Ratio of time period is  0.1  and ratio of speed is  1.0  .

EXAMPLE NUMBER 8.12 : (Page Number 305)

In [162]:
import math
   #Given that
r1 = 1.5e8    # distance of Earth from Sun in km
t1 = 1    # let 
print "  Standard formula used T**2 = k* r**3"
t2 = 29.5 * t1   # calculation of time period of Saturn
r2 = r1 * (t2 / t1) ** (2/3)    #calculation of distance of stern from Sun

print "   Distance of Saturn from Sun is ",r2," km ."
  Standard formula used T**2 = k* r**3
   Distance of Saturn from Sun is  150000000.0  km .

EXAMPLE NUMBER 8.13 : (Page Number 305)

In [165]:
import math
   #Given that
r_peri = 360    # distance of perigee of satellite from Earth surface in km
r_apo = 2500    # distance of apogee of satellite from Earth surface in km
R_e = 6400    # radius of Earth in km
v_p = 30000    # speed of satellite at apogee position in km/h
print "  Standard formula used v * r = k "
r_p = r_peri + R_e    # calculation of distance of perigee
r_a = r_apo + R_e   # calculation of distance of apogee
v_a = v_p * r_p / r_a    # calculation of speed at apogee
print "   Speed at perigee is ",v_p," km/h and at apogee is ",v_a," km/h ."
  Standard formula used v * r = k 
   Speed at perigee is  30000  km/h and at apogee is  22786  km/h .

EXAMPLE NUMBER 8.14 : (Page Number 306)

In [168]:
import math
   #Given that
h = 600    # distance of satellite from surface of Earth in km
R_e = 6400    # radius of Earth in km
m_s = 100     # mass of satellite in kg
g = 10    # gravitational acceleration in m/s2 
v_y = 2500    # upward velocity of launched satellite
print "  Standard formula used 1/2 *(m_s * v **2 / r) = g * R_E**2 * m /R_e**2 "
r = R_e + h   # calculation of effective height of satellite

v = math.sqrt (g * (R_e * 1e3)**2 / (r * 1e3))    # calculation of orbital velocity of satellite

P_x = m_s * v   # calculation of momentum in x direction
P_y = m_s * v_y   # calculation of momentum in y direction
U = math.sqrt(P_x**2 + P_y**2 )    # calculation of magnitude of impulse required

theta1 = (180 / pi) * math.atan (P_y / P_x )    # calculation of direction of impulse required
print "  Magnitude and direction of impulse required are respectively ",round(U,4),"kgm/s and ",round(theta1,4)," degree."
  Standard formula used 1/2 *(m_s * v **2 / r) = g * R_E**2 * m /R_e**2 
  Magnitude and direction of impulse required are respectively  804762.6092 kgm/s and  18.1076  degree.

EXAMPLE NUMBER 8.15a : (Page Number 306)

In [169]:
import math

   #Given that
b_e = 13.6    # Binding energy of electron to proton in eV
c= 3e8    # speed of light in m/s
print "  Standard formula used E = m*c**2"
del_m = b_e * (1.6e-19) / c**2 * 1000 
print "  Loss in mass during formation of 1 atom of hydrogen is ",del_m," g."
  Standard formula used E = m*c**2
  Loss in mass during formation of 1 atom of hydrogen is  2.41777777778e-32  g.

EXAMPLE NUMBER 8.15b : (Page Number 306)

In [170]:
import math
   #Given that
M_p = 1.6725e-24    # mass of proton in g
M_n = 1.6748e-24    # mass of neutron in g
M_d = 3.3433e-24    # mass of deuteron in g
c= 3e8    # speed of light in m/s
print "  Standard formula used E = m*c**2"
del_m = M_p + M_n - M_d    # calculation of Loss in mass during formation of 1 atom of hydrogen

b_e = (del_m / 1000) * c**2 / (1.6e-19 * 1e6)    # calculation of Binding energy of deuteron

print "  Binding energy of deuteron is ",b_e," MeV."
  Standard formula used E = m*c**2
  Binding energy of deuteron is  2.25  MeV.