In [1]:

```
#given
m=1 #Mass of torsional pendulum in kg
R=0.06 #Radius of torsional pendulum in m
l=1.2 #Length of the wire in m
r=0.0008 #Radius of wire in m
S=(9*10**9) #Modulus of rigidity of the material in N/m^2
#Calculations
import math
I=(1/2.0)*m*R**2
C=(3.14*S*r**4)/(2*l)
T=2*3.14*math.sqrt(I/C)
#Output
print"Period of pendulum is ",round(T,1),"s"
```

In [4]:

```
#given
l=0.8 #Length of the wire in m
d=(1.8*10**-3) #Diameter of the wire in m
a=1.5 #Angle of twist in degrees
S=(1.8*10**11) #Modulus of rigidity of the material in N/m^2
#Calculations
r=(a*3.14)/180.0
W=((3.14*S*(d/2.0)**4*r**2)/(4*l))/10.0**-5
#Output
print"Work required to twist the wire is ",round(W,2),"*10^-5 J"
```

In [7]:

```
#given
l=2 #Length of wire in m
d=(0.4*10**-3) #Diameter of the wire in m
x=(1.03*10**-3) #Extension in length in m
L=2 #Load in kg
C=(4.52*10**-6) #Couple in N/m
a=0.03 #Twist angle in radians
#Calculations
Y=((L*9.8*l)/(x*3.14*(d/2.0)**2))/10**11
S=((C*2*l)/(3.14*(d/2.0)**4*a))/10**11
s=(Y/(2*S))-1
#Output
print"Youngs modulus is ",round(Y,2),"*10**11 N/m^2"
print"Modulus of rigidity is ",round(S,2),"*10**11 N/m^2"
print"Poissons ratio is ",round(s,2)
```

In [8]:

```
#given
r=0.003 #Radius of drop of glycerine in m
T=(63.1*10**-3) #Surface tension of glycerine in N/m
#Calculations
P=((2*T)/r)
#Output
print"Excess pressure inside the drop of glycerine is ",round(P,2),"N/m^2"
```

In [5]:

```
#given
r1=0.001 #Initial radius in m
r2=0.004 #Final radius in m
t=2*10**-3 #Time in s
s=(7*10**-2) #Surface tension of water in N/m
#Calculations
P=((2*s)*((1/r2)-(1/r1)))/(t*10**4)
#Output
print"Rate of change of pressure is ",P,"*10**4 N/m**2 s"
```

In [9]:

```
#given
d=0.02 #Diamter of soap bubble in m
s=(25*10**-3) #Surface tension in N/m
#Initial surface area of the bubble is zero and final area is 2*4*pie*r^2 where r is the radius of the bubble
#Calculations
W=(s*2*4*3.14*(d/2.0)**2)/10.0**-5
#Output
print"Work done in blowing a soap bubble is ",W,"*10**-5 J"
```

In [8]:

```
#given
r=0.01 #Radius of liquid drop in m
n=500 #Number of drops
s=(63*10**-3) #Surface tension in N/m
#Calculations
r1=(((4*3.14*r**3)/3.0)/((n*4*3.14)/3.0))**(1/3.0)
As=(n*4*3.14*r1**2)
A=4*3.14*r**2
W=(s*(As-A))/10.0**-4
#Output
print"Energy required to break up a drop of a liquid is ",round(W,1),"*10**-4 J"
```

In [10]:

```
#given
d=0.04 #Inside diameter of garden hose in m
D=0.01 #Diamter of nozzle opening in m
v1=0.6 #speed of flow of water in the hose in m/s
#calculations
a=3.14*(d/2.0)**2
A=3.14*(D/2.0)**2
v2=(v1*a)/A
#Output
print"Speed of flow through the nozzle is ",v2,"m/s"
```