It’s c the same thing that is the same
(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.
Processes in which matter changes between liquid and gaseous states are vaporization, evaporation, and condensation.
Answer:
B.Include as many details as possible when writing the conclusion.
This helps improve the quality of their experiment..
_Askmeanything2♡
Answer:
v = 19.6 m/s.
Explanation:
Given that,
The radius of the circle, r = 5 m
The time period of the ball, T = 1.6s
We need to find the ball's tangential velocity.
The formula for the tangential velocity is given by :

Putting all the values in the above formula

So, the tangential velocity of the ball is 19.6 m/s. Hence, the correct option is (c).