Answer:
Explanation:
given,
speed of wind, = 14 m/s
frequency of horn,f_s = 1000 Hz
speed of sound,V = 344 m/s
frequency heard by the listener
using Doppler effect
f_L is the frequency of the sound heard by the listener
f_s is the frequency of sound emitted by the listener
V is the speed of sound
v_L is the speed of listener
v_s is the speed of source
now,
considering the frame of reference in which wind is at rest now, both listener and the source will be moving at 14 m/s
now on solving we will get
hence, the frequency heard by the listener is equal to 1000 Hz
Answer: 6.65 rad/s
Explanation:
Firstly, we need to know that according the kinetic theory of gases, the average kinetic energy 
of a molecule with 
degrees of freedom is:
(1)
Where:
because oxigen is a diatomic molecule and has 5 degrees of freedom
is the Boltzman constant
is the temperature
Then:
(2)
(3) With this value of average kinetic energy we can find the average angular velocity, with the following equation:
(4)
Where:
is the moment of inertia
is the angular velocity
Now, 
(5)
Being 
the molar mass of Oxigen molecule and 
the distance between atoms
(6)
(7)
Substituting (7) and (3) in (4):
(8)
Finding :
(9) This is the average angular velocity for a molecule of O2
Answer:
24 N
Explanation:
Given,
Unstretched length or original length , x1 = 12cm
Stiffness constant, k = 8 N/cm
Load required to take spring to a length , x2 of 15cm
Recall the relation :
F = Ke
Where, e = extension
e = x2 - x1
e = (15 - 12) = 3
F = ke
F = 8 N/cm * 3cm
F = 24 N/cm*cm
F = 24 N
Hence, required load = 24 N
