I was going to beg off until tomorrow, but this one is nothing like those others.
Why, at only 40km/hr, we can ignore any relativistic correction, and just go with Newton.
To put a finer point on it, let's give the car a direction. Say it's driving North.
a). From the point of view of the car, its driver, and passengers if any,
the pole moves past them, heading south, at 40 km/hour .
b). From the point of view of the pole, and any bugs or birds that may be
sitting on it at the moment, the car and its contents whiz past them, heading
north, at 40 km/hour.
c). A train, steaming North at 80 km/hour on a track that exactly parallels
the road, overtakes and passes the car at just about the same time as
the drama in (a) and (b) above is unfolding.
The rail motorman, fireman, and conductor all agree on what they have
seen. From their point of view, they see the car moving south at 40 km/hr,
and the pole moving south at 80 km/hr.
Now follow me here . . .
The car and the pole are both seen to be moving south. BUT ... Since the
pole is moving south faster than the car is, it easily overtakes the car, and
passes it . . . going south.
That's what everybody on the train sees.
==============================================
Finally ... since you posed this question as having something to do with your
fixation on Relativity, there's one more question that needs to be considered
before we can put this whole thing away:
You glibly stated in the question that the car is driving along at 40 km/hour ...
AS IF we didn't need to know with respect to what, or in whose reference frame.
Now I ask you ... was that sloppy or what ? ! ?
Of course, I came along later and did the same thing with the train, but I am
not here to make fun of myself ! Only of others.
The point is . . . the whole purpose of this question, obviously, is to get the student accustomed to the concept that speed has no meaning in and of itself, only relative to something else. And if the given speed of the car ...40 km/hour ... was measured relative to anything else but the ground on which it drove, as we assumed it was, then all of the answers in (a) and (b) could have been different.
And now I believe that I have adequately milked this one for 50 points worth.
Answer:
Q9. Man who received the most altercations for a theory which later on became a revolutionary theory influenced in many areas of modern science and technology.
Q10. Fire truck is coming towards you
Explanation:
Q9. Christian Doppler was born on 29th of November 1803 in Saltzburg. After studies in Linz and Vienna, he graduated in Mathematics. For many years, Doppler struggled to find work in academia, and for a time he worked as a bookkeeper at a factory. His academic career took him from Austria to Prague, where he became assistant at the University and later worked as professor in Prague. Back to Vienna, he was appointed as professor at the Polytechnic School and in 1850 as first director of the new Institute of Physics. While working at Vienna, his health broke down and moved Venice where he sought his eternal rest on March 17th, 1953.
During his lifetime, the man was quite controversial: a personality praised by some, but detested by others; and even as a scientist, he had a difficult time. He did publish papers on magnetism, electricity, optics and astronomy but, the discovery that allowed him to remain in history of science was the one he presented at Royal Bohemian Society of Science entitled "On the colored light of the double stars and certain other stars of the heavens" in 1842. He hypothesized that the pitch of the sound would change if the source was moving.
Doppler's ideas were initially received with a certain amount of skepticism so, in order to support his claims, he devised an experiment in 1845 with the help of colleague. He used two sets of trumpeters, one set stationary at a train station and one set moving on an open train car. Both sets of musicians had perfect pitch and held the same note. As the train passed the station, it was obvious that the frequency of the two notes didn't match, even though the musicians were playing same note. This proved his hypothesis.
Demonstrating that the Doppler effect also held true for frequency of ligh proved more difficult and was never successfully achieved before Doppler's demise. The first experiment that revealed a Doppler shift in starlight was carried out at the beginning of twentieth century. Since then Doppler effect was proved invaluable for astronomical observations.
For the most of the academic world, he is known as physicist; but one can equally find him on the list of mathematicians and astronomers too. This is proof for the exceptional broad spectrum of application of his main discovery.
Q10. When there is increase in frequency of the sound from source, then the source is moving towards you. Hence the fire truck is coming towards you
Answer:
For cast iron we have
For copper
For Lead
For Zinc
Explanation:
As we know that final speed of the block is calculated by work energy theorem
now we have
now we have
For cast iron we have
For copper
For Lead
For Zinc
Answer:
Fighting
Explanation:
Fighting with someone like punch for punch can make the person bleed which an injury to the guy who you fought with and you can be arrested if the parents file a complain at the police station
