I believe it's People interacting. I hope i've helped you! (:
Answer:mechanical waves.
Explanation:
Mechanical waves require the particles of the medium to vibrate in order for energy to be transferred. For example, water waves, earthquake/seismic waves, sound waves, and the waves that travel down a rope or spring are also mechanical waves.
Answer:
Another term for free enterprise system would be capitalism
Answer:
Explanation:
Given that the airplane starts from the rest (this is initial velocity equals to zero) and accelerates at a constant rate, position can be described like this: 
where x is the position, t is the time a is the acceleration and 
is initial velocity. In this way acceleration can be found. 
.
Now we are able to found velocity at any time with the formula: 
