Long Riddles and Answers

Question: I move faster in certain solids, but slower in certain gases. I am typically broken by objects with large masses. I can be used as for pleasure, practice, and even an alarm. If used excessively, I can cause harm. What am I?

Question: I give you a family of three:

One is sits down, and will never get up.
The second eats as much as is given to him, yet is always hungry.
The third goes away and will never return.

What are they?

Question: A man goes down to the beach and starts walking on the beach, he has to get to the circus in a hurry and so he practices his act on the way, even though he had walked for an hour his feet weren't the least bit tired, why?

Question: It's not a baby though you hold in the arms close to your bosom. It's not an Indian man though it has long beard. It's not a monkey though its tail is bent. It's not a bird though it has beautiful voice. What am I?

Question: I have memories, but none of my own,
whatever's on my inside is what is shown.
If I'm ever different it's because you changed me,
I feel like a decoration, here for you to arrange me.

What am I?