To solve this problem it is necessary to apply the concepts related to Dopler's Law. Dopler describes the change in frequency of a wave in relation to that of an observer who is in motion relative to the Source of the Wave.
It can be described as

c = Propagation speed of waves in the medium
= Speed of the receiver relative to the medium
= Speed of the source relative to the medium
Frequency emited by the source
The sign depends on whether the receiver or the source approach or move away from each other.
Our values are given by,
Velocity of car
velocity of motor
Velocity of sound
Frequency emited by the source
Replacing we have that



Therefore the frequency that hear the motorcyclist is 601.7Hz
[I researched for you, since I am not in that particular level to know that knowledge yet. I assure this is accurate info :)]
The answer is A, red.
"Remember, the color you see is light REFLECTING off the surface of that object. If all colors are absorbed in to the surface EXCEPT red, red must be reflected, and you'll see red." - Yahoo User @Chap
Some of the reasons that can cause can earthquake are volcanic eruptions, the grinding of tectonic plates beneath the earth's crust and violent explosions which can be artificially induced as well. No matter what the reason is, earthquakes affect the environment and earth's surface. Noticeable cracks have formed on the earth's surface after earthquakes. If the tremors are violent, it can result in the destruction of landscapes. The mountains become prone to land sliding. the glacier's become a threat because of fear of avalanches. tsunamis which are earthquakes in the ocean bed can cause heavy flooding which causes water to cross all boundaries and shores and flood entire cities. Earthquakes caused by volcanoes can result in the spewing of so much lava that it may spill everywhere and cool changing the surface of the earth geologically as well as the ash causing aerial pollution.
PV = 400 x 0.08 = 32 J
Hope this helps