Answer:
D.vibrations that cause changes in air pressure
Explanation:
Sound is a type of wave.
A wave is a periodic disturbance/oscillation that trasmits energy without transmitting matter. There are two different types of waves:
- Transverse waves: in a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. These waves are characterized by the presence of crests (points of maximum positive displacement) and troughs (points of maximum negative displacement). Examples of transverse wave are electromagnetic waves.
- Longitudinal waves: in a longitudinal wave, the direction of the oscillation is parallel to the direction of motion of the wave. These waves are characterized by the presence of compressions (regions where the density of particle is higher) and rarefactions (regions where the density of particle is lower). Examples of longitudinal waves are sound waves.
Sound waves, in particular, consist of vibrations of the particles in a medium - most commonly, air - that occur back and forth along the direction of motion of the wave. Because of these motion, the air will have areas of higher pressure (which correspond to the compressions), where the density of particles is higher, and areas of lower pressure (which correspond to the rarefactions), where density of particles is lower.
Atomic Number
or
Number of Protons
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Answer:
Explanation:
Call the bike on the right A
Call the bike on the left B
The car begins it's time when it passes A
4 minutes later, it passes B.
But B has moved in 4 minutes and that is the key to the problem.
How far has B moved.
t = 4 minutes = 4/60 hours = 1/15 of an hour.
d = ?
rate = 30 km / hr
d = r * t
d = 30 km/hr * 1/15 hours = 2 km
The distance between the bikes is 5 km.
So the car has traveled 5 - 2 = 3 km
d = 3 km
r = ?
t = 4 minutes = 1/15 hour
r = d/t = 3/(1/15)= 3 / 0.066666666 = 45 km/hr.
It is called the CMBR, which stands for cosmic microwave background radiation. It was discovered by Arno Penzias and Robert Wilson in 1964.
