Answer:
C.The car appears to be moving 30 km/hr in the opposite direction of the bus.
Explanation:
There are two reference systems involved in this situation:
- Reference system S: this is the reference system where velocities are measured with respect to the ground. In this reference system, the car is parked, so its velocity is
- Reference system S': this is the reference system moving with the bus. This reference system is moving with a velocity of
with respect to the reference system S
Calling
the velocity of the car in the reference system S', we have:

From which

and the negative sign means that a passanger in the bus observes the car moving in the opposite direction.
The amplitude of the red colored wave is 1 unit and the amplitude of the red colored wave is 2.1 unit.
<h3>
What is amplitude of a wave?</h3>
The amplitude of a wave is the maximum displacement of the wave. It can also be described at the maximum upward displacement of a wave curve.
<h3>Amplitude of the red colored wave</h3>
From the graph, the amplitude of the red colored wave is 1 unit.
<h3>Amplitude of the blue colored wave</h3>
From the graph, the amplitude of the red colored wave is 2.1 unit.
Thus, the amplitude of the red colored wave is 1 unit and the amplitude of the red colored wave is 2.1 unit.
Learn more about amplitude here: brainly.com/question/3613222
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I think these gases are water vapor and nitrogen. As the temperature rises, these water vapor molecules, would condense and form the oceans we have. Also, it was said that in the early atmosphere, nitrogen is very abundant and even today the composition of air is 79% by volume.