Explanation:
You need two, maybe three things - something that's vibrating, a medium for those vibrations to propagate in, and a listener to hear it or recording equipment to pick it up
Explanation:
A compound is a pure substance composed of two or more different atoms chemically bonded to one another. A compound can be destroyed by chemical means. It might be broken down into simpler compounds, into its elements or a combination of the two.
Answer:

Explanation:
The acceleration of an object is given by Newton's second law:

where
F is the net force applied on the object
m is the mass of the object
For the book in the problem, we have:
is the mass
is the force applied
Substituting into the formula, we find the acceleration:

Yes the Earth is bigger than the Moon.
The moon is one-quarter the size of Earth.