(a) 646.9 Hz
The formula for the Doppler effect is:
where
f = 600 Hz is the real frequency of the sound
f' is the apparent frequency
v = 345 m/s is the speed of sound
is the velocity of the observer (zero since it is stationary at the station)
is the velocity of the source (the train), moving toward the observer
Substituting into the formula,
(b) 20.1 m/s
In this case, we have
f = 600 Hz is the real frequency
f' = 567 Hz is the apparent frequency
Assuming the observer is still at rest,
so we can re-arrange the Doppler formula to find 
, the new velocity of the train:
and the negative sign means the train is moving away from the observer at the station.
Regular reflections occurs when light reflects off a very smooth surface and forms a clear image.
Diffuse reflection: occurs when light reflects off a rough surface and forms a blurry image or no image at all.
Similarities: they both hit the surface, but the difference is one of them give clear image the other one gives blurry image or no image at all.
Hope this helped!
Types of Air Resistance: There are three main types of drag in aerodynamics – Lift Induced, Parasitic, and Wave. Each affects an objects ability to stay aloft as well as the power and fuel needed to keep it there.
89 degrees Fahrenheit would be 31.7 degrees Celsius!
