Explanation:
Let
and 
The sum of the two vectors is


The difference between the two vectors can be written as


Since they are both examples of moving waves, they both transmit energy.
Use the definition of acceleration:
Acceleration = (change of velocity) divided by (time for the change)
The graph says:
Change of velocity = -6 m/s
Time for the change = 3 sec
So Acceleration = (-6m/s) / (3 s)
That's -6/3 m/s•s
or
-2 m/s^2
Answer: c
Explanation:
C Air is a compound of two or more components that keep their own identifying properties, while water is composed of mixtures that combine to form a compound.