<span>from a trough to the rest position and from a crest to the rest position.
</span>
Answer:
The stress is 
Explanation:
From the question we are told that
The diameter of the post is 
The length is 
The weight of the loading mass
Generally the radius of the post is mathematically represented as

=> 
Generally the area of the post is

=> 
=> 
Generally the weight exerted by the load is mathematically represented as

=> 
=> 
Generally the stress is mathematically represented as

=> 
=> 
it would be a chain reaction and a wave
External = R
Internal = r
Volume of hemisperical = 2/3 π(R³-r³)
V= 2/3 π(9.1³ - 8.4³)
V= 336.9 cm³