(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.
Answer: A) True, you are correct
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Explanation:
Power in physics is defined as
power = (change in work)/(change in time)
which shows that power is basically the rate of work done. We can think of it like a speed of sorts.
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For example, if you apply 100 joules of work over 2 seconds, then,
power = (100 joules)/(2 seconds)
power = (100/2) joules per second
power = 50 watts
A watt is defined to be a joule per second, and it's often used to measure how much electricity is consumed, but it has broader uses in physics as well.
For harmer:-
initial velocity=u=0m/s
Acceleration due to gravity=10m/s^2
Now
For soft drink:-
u=24m/s
Using eq(1)
After 1.2s they will meet.
Now
putting t in eq(1)
At the height of 7.2m they will meet
