1. 168.1 Hz
To find the apparent frequency heard by the driver in the car, we can use the formula for the Doppler effect:

where
f is the original sound of the horn
v is the speed of sound
is the velocity of the observer (the driver and the car), which is positive if the observer is moving towards the source and negative if it is moving away
is the velocity of the sound source (the train), which is positive if the source is moving away from the observer and negative otherwise
In this problem we have, according to the sign convention used:

Substituting, we find:

2. 
The speed of light can be calculated as

where
d is the distance travelled
t is the time taken
In this problem:
is the total distance travelled by the laser beam (twice the distance between the Earth and the Moon)
t = 2.60 s is the time taken
Substituting in the formula,

Answer:
It includes earthwork, trenching, wall shafts, tunneling and underground
Explanation:
Explanation:
It is known that relation between torque and angular acceleration is as follows.

and, I = 
So, 
= 4 


So, 
= 1 
as 
=
Hence, 

Thus, we can conclude that the new rotation is
times that of the first rotation rate.
Normally a storm surge.
Experience: I lived through Andrew and Wilma
The best and most correct answer among the choices provided by the question is <span>a.The Three Laws of Planetary Motion, Principia Astronomica. </span>
Hope my answer would be a great help for you.
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