Answer:
Longitudinal waves have the same direction of vibration as their direction of travel. This means that the movement of the medium is in the same direction as the motion of the wave.
Given parameters:
First velocity = 2.50m/s
Time of travel = 3s
Second velocity = 1.50m/s
Unknown:
The displacement during the first interval = ?
Velocity is the displacement of a body with time. Displacement is a distance move in a specific direction by a body.
Velocity = 
So;
Displacement = Velocity x Time taken
Now input the parameter for the first velocity and time of travel;
Displacement = 2.5 x 3 = 7.5m
The displacement id 7.5m
Carbon atoms can form straight, and branched chains, and rings
Answer;
D. rocket engines are not dependent on oxygen from the air.
Explanation;
-Jet engines and rockets work on the same principle. They produce thrust through an internal pressure difference and, as explained by Newton’s Third Law of Motion, eject exhaust gases in an equal and opposite direction.
-The main difference between them is that jets get the oxygen to burn fuel from the air and rockets carry their own oxygen, which allows them to operate in space.
Additionally, Jet engines have two openings (an intake and an exhaust nozzle). Rocket engines only have one opening (an exhaust nozzle).