Answer:
the first one is D
Explanation:
so if the others u put are right the the second would be c
I believe it is Acoustics, the real name for it would be like Reverberation. But go with Acoustics. :)
Answer:
9 cm.
Explanation:
The energy used for stretch the spring from
to
will be ,
The energy used for stretch the spring from
to
will be ,
using the energy of spring formula ,we find that


Dividing both the equation will get,

Therefore, the natural length of the spring is, 9 cm.