20m/s, honestly I have know idea what the asnwer is but if i had to guess, this would be my answer.
Answer:
it's all around you and it can't be destroyed
Answer:
True
Explanation:
an object in motion stays in motion unless acted upon by another force
Level of sound is related to intensity by this equation

given that
L = 85 dB
also we know that

now we have

By solving above equation


now above is the intensity due to two firecrackers and if we wish to find the sound level of one firecracker then we will find its half level intensity


now again by above formula

