Answer:
D. The frequency is not affected as the volume of sound increases
Explanation:
Volume of the sound is defined by the amplitude of the wave or how loud a sound is whereas Frequency is basically the pitch of the sound and is inversely proportional to the wavelength . Increasing frequency will increase the pitch of the sound without affecting it's volume.
Jogging side by side since the speed is equal and the direction is the same i.e same velocity
To solve the exercise it is necessary to take into account the concepts of wavelength as a function of speed.
From the definition we know that the wavelength is described under the equation,

Where,
c = Speed of light (vacuum)
f = frequency
Our values are,


Replacing we have,



<em>Therefore the wavelength of this wave is
</em>
Answer:
Explanation:
Given
Each student exert a force of 
Let mass of car be m
there are 18 students who lifts the car
Total force by 18 students 
therefore weight of car 
mass of car 

(b)