Answer:
Part a)

Part b)

Explanation:
Part a)
Level of sound = 75 dB
now we know that

here we know that

now we have


Part b)
Intensity of sound wave is given as

here we know that

so we have


now we know



now we have


Answer:

Explanation:
The kinetic energy possessed by particles will be

where,
M is the mass of the particle (7920938.3 MeV/c²)
c is the speed of the light
Also,
energy of the proton particle = 
where,
v is the velocity
m_p is the mass of the proton (938.3 MeV/c²)
since the energy is equal
thus,

or
![1-\frac{v^2}{c^2}=[\frac{2m_p}{M}]^2](https://tex.z-dn.net/?f=1-%5Cfrac%7Bv%5E2%7D%7Bc%5E2%7D%3D%5B%5Cfrac%7B2m_p%7D%7BM%7D%5D%5E2)
substituting the values in the above equation, we get
![1-\frac{v^2}{c^2}=[\frac{2\times 938.3 }{7920}]^2](https://tex.z-dn.net/?f=1-%5Cfrac%7Bv%5E2%7D%7Bc%5E2%7D%3D%5B%5Cfrac%7B2%5Ctimes%20938.3%20%7D%7B7920%7D%5D%5E2)
or

Hence,<u> the speed necessary for the specified condition to occur is </u><u>0.9714 times the speed of the light</u>