# Chapter 3: The Laws of Motion¶

## Example 3.4 , Page no:18¶

In [1]:
import math
from __future__ import division

#initialisation of variables
g=9.8; #gravitational constant in m/sec square
m=100; #mass in kg

#CALCULATIONS
a=(m*g);

#RESULTS
print"Weight in Newton =",round(a);

Weight in Newton = 980.0


## Example 3.5 , Page no:18¶

In [2]:
import math
from __future__ import division

#initialisation of variables
g=9.8; #gravitational constant in m/sec square
m=5; #mass in kg
F=100; #force in Newton

#CALCULATIONS
w=(m*g);
a=F/m; #calculating acc.

#RESULTS
print"Weight in Newton =",round(w);
print"Accelaration in m/sec square =",round(a);

Weight in Newton = 49.0
Accelaration in m/sec square = 20.0


## Example 3.6 , Page no:18¶

In [3]:
import math
from __future__ import division

#initialisation of variables
g=9.8; #gravitational constant in m/sec square
m=1; #mass in kg
F=1; #force in Newton
w=1; #in Newton

#CALCULATIONS
a=F/m; #calculating acc.
a2=(F*g)/w;

#RESULTS
print"Accelaration in m/sec square =",round(a);
print"Accelaration in m/sec square = ",round(a2,2);

Accelaration in m/sec square = 1.0
Accelaration in m/sec square =  9.8


## Example 3.7 , Page no:18¶

In [4]:
import math
from __future__ import division

#initialisation of variables
g=9.8; #gravitational constant in m/sec square
m=10; #mass in kg
a=5; #acc. in m/sec square

#CALCULATIONS
F=m*a; #calculating force

#RESULTS
print"Force in Newton =",round(F);

Force in Newton = 50.0


## Example 3.8 , Page no:18¶

In [5]:
import math
from __future__ import division

#initialisation of variables
a=20; #acc. in m/sec square
F=80; #force in Newton

#CALCULATIONS
m=F/a; #using F=m*a (Newton's Law)

#RESULTS
print"Mass in kg =",round(m);

Mass in kg = 4.0


## Example 3.9 , Page no:19¶

In [6]:
import math
from __future__ import division

#initialisation of variables
g=9.8; #gravitational constant in m/sec square
m=60; #mass in kg
a=2; #acc. in m/sec square

#CALCULATIONS
F=(m*g)+(m*a); #calculating force in Newton

#RESULTS
print"Force in Newton =",round(F);

Force in Newton = 708.0


## Example 3.10 , Page no:19¶

In [7]:
import math
from __future__ import division

#initialisation of variables
m=1500; #mass in kg
F=3000; #force in Newton
t=5; #time in sec

#CALCULATIONS
a=F/m; #calculating acc. (Newton's Law)
v=a*t; #kinematical equation

#RESULTS
print"Accelaration in m/sec square =",round(a);
print"Velocity in m/sec =",round(v);

Accelaration in m/sec square = 2.0
Velocity in m/sec = 10.0


## Example 3.11 , Page no:19¶

In [8]:
import math
from __future__ import division

#initialisation of variables
m=2000; #mass in kg
a=1; #acc. in m/sec square
m1=3000; #mass in kg

#CALCULATIONS
F=m*a; #Newton's Law
a=F/m1; #Newton's Law

#RESULTS
print"Force in Newton =",round(F,3);
print"Accelaration in m/sec square = ",round(a,3);

Force in Newton = 2000.0
Accelaration in m/sec square =  0.667


## Example 3.12 , Page no:19¶

In [9]:
import math
from __future__ import division

#initialisation of variables
v=20; #velocity in m/sec
v0=10; #velocity in m/sec
t=5; #time in sec
m=1000; #mass in kg
a1=2; #acc. in m/sec square

#CALCULATIONS
a=(v-v0)/t; #kinematical equation
F=m*a; #Newton's Law

#RESULTS
print"Accelaration in m/sec square =",round(a);
print"Force in Newton =",round(F);

Accelaration in m/sec square = 2.0
Force in Newton = 2000.0


## Example 3.13 , Page no:19¶

In [10]:
import math
from __future__ import division

#initialisation of variables
v=-20; #velocity in m/sec
v0=15; #velocity in m/sec
t=0.005; #time in sec
m=0.06; #mass in kg

#CALCULATIONS
a=(v-v0)/t; #kinematical equation
F=m*a; #Newton's Law

#RESULTS
print"Accelaration in m/sec square =",round(a);
print"Force in Newton =",round(F);

Accelaration in m/sec square = -7000.0
Force in Newton = -420.0


## Example 3.14 , Page no:20¶

In [11]:
import math
from __future__ import division

#initialisation of variables
m=1000; #mass in kg
F=3000; #force in Newton
v0=30; #initial velocity in m/sec
v=0; #final velocity in m/sec
a1=-3; #acc. inm/sec square

#CALCULATIONS
a=F/m; #calculating acc.
t=v0/a; #uisng kinematical equation
s=(v0*t)+(1/2)*(a1*t*t); #kinematical equation

#RESULTS
print"Accelaration in m/sec square = ",round(a);
print"Time in sec =",round(t);
print"Distance in m =",round(s);

Accelaration in m/sec square =  3.0
Time in sec = 10.0
Distance in m = 150.0


## Example 3.15 , Page no:20¶

In [12]:
import math
from __future__ import division

#initialisation of variables
g=32; #gravitational constant in ft/sec square
m=50; #mass in slugs
w1=50; #weight in lb

#CALCULATIONS
w=m*g; #calculating weight in lb
m=w1/g; #calculating mass in slugs.

#RESULTS
print"Weight in lb =",round(w);
print"Mass in slugs =",round(m,3);

Weight in lb = 1600.0
Mass in slugs = 1.563


## Example 3.16 , Page no:20¶

In [13]:
import math
from __future__ import division

#initialisation of variables
g=32; #gravitational constant in ft/sec square
w=160; #weight in lb

#CALCULATIONS
m=w/g #calculating mass in slugs.

#RESULTS
print"Mass in slugs =",round(m);

Mass in slugs = 5.0


## Example 3.17 , Page no:20¶

In [14]:
import math
from __future__ import division

#initialisation of variables
m=25; #mass in slugsg
F=75; #force in lb
t=12; #time in sec

#CALCULATIONS
a=F/m; #calculating acc.
v=a*t; #kinematical equation

#RESULTS
print"Accelaration in ft/sec square =",round(a);
print"Velocity in ft/sec =",round(v);

Accelaration in ft/sec square = 3.0
Velocity in ft/sec = 36.0


## Example 3.18 , Page no:21¶

In [15]:
import math
from __future__ import division

#initialisation of variables
F=150; #force in lb
g=32; #gravitational constant in ft/sec square
w=96; #weight in lb

#CALCULATIONS
m=w/g; #calculating mass
a=F/m; #calculating acc

#RESULTS
print"Mass in slugs =",round(m);
print"Accelaration in ft/sec square =",round(a);

Mass in slugs = 3.0
Accelaration in ft/sec square = 50.0


## Example 3.19 , Page no:21¶

In [16]:
import math
from __future__ import division

#initialisation of variables
g=32; #gravitational constant in ft/sec square
w=3200; #weight in lb
v=44; #velocity in ft/sec
t=8; #time in sec

#CALCULATIONS
m=w/g; #calculating mass
a=v/t; #calculating acc
F=m*a; #calculating force in lb

#RESULTS
print"Mass in slugs =",round(m);
print"Accelaration in ft/sec square =",round(a,3);
print"Force in lb =",round(F);

Mass in slugs = 100.0
Accelaration in ft/sec square = 5.5
Force in lb = 550.0


## Example 3.20 , Page no:21¶

In [17]:
import math
from __future__ import division

#initialisation of variables
g=32; #gravitational constant in ft/sec square
w=2400; #weight in lb
F=750; #force in lb
m=75; #mass in slugs
v0=60; #initial velocity in ft/sec
v=20; #final velocity in ft/sec
a1=-10; #acc. in ft/sec square

#CALCULATIONS
m=w/g; #calculating mass
a=F/m; #calculating acc
t=(v-v0)/a1; #kinematical equation
s=(v0*t)+((1/2)*a1*t*t); #calculating distance in ft

#RESULTS
print"Mass in slugs =",round(m);
print"Accelaration in ft/sec square =",round(a);
print"Distance in ft =",round(s);

Mass in slugs = 75.0
Accelaration in ft/sec square = 10.0
Distance in ft = 160.0


## Example 3.21 , Page no:21¶

In [18]:
import math
from __future__ import division

#initialisation of variables
g=32; #gravitational constant in ft/sec square
w=3200; #weight in lb
F=800; #force in lb
m1=100; #mass in slugs

#CALCULATIONS
m=w/g; #calculating mass
a=F/m1; #calculating acc

#RESULTS
print"Mass in slugs =",round(m);
print"Accelaration in ft/sec square =",round(a);

Mass in slugs = 100.0
Accelaration in ft/sec square = 8.0


## Example 3.22 , Page no:21¶

In [19]:
import math
from __future__ import division

#initialisation of variables
F=50-30; #force in lb
w1=50; #weight in lb
w2=30; #weight in lb

#CALCULATIONS
m=(w1+w2)/g; #calculating mass
a=F/m; #Newton's Law

#RESULTS
print"Mass in slugs =",round(m,3);
print"Accelaration in ft/sec square =",round(a);

Mass in slugs = 2.5
Accelaration in ft/sec square = 8.0