Answers all in picture below
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Explanation:
There are two components of a longitudinal sound wave which are compression and rarefaction. Similarly, there are two components of the transverse wave, the crest, and trough.
The crest of a wave is defined as the part that has a maximum value of displacement while the trough is defined as the part which corresponds to minimum displacement.
While compression is that space where the particles are close together while the rarefaction is that space where the particles are far apart from each other.
So, the refraction or the rarefied part of a longitudinal sound wave is analogous to a trough of a transverse wave.
Answer:

Explanation:
Here we can use energy conservation
As per energy conservation conditions we know that work done by external source is converted into kinetic energy of the disc
Now we have

now we know that work done is product of force and displacement
so here we have


now for moment of inertia of the disc we will have



now from above equation we will have


See this. I hope you find your answer
In this case to find the weight of an object you must use the formula.
W = mg