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garri49 [273]
3 years ago
7

Please Help!

Physics
1 answer:
e-lub [12.9K]3 years ago
3 0

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

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PLZ EXPLAIN IM SO CONFUSED AND THIS IS DUE TONIGHT. I WILL GIVE 50 POINTS!
bezimeni [28]

When you first pull back on the pendulum, and when you pull it back really high the Potential Energy is high and the Kinetic Energy is low, But when up let go, and it gets right around the middle, that's when the Potential energy transfers to Kinetic, at that point the kinetic Energy is high and the potential Energy is low. But when it comes back up at the end. The same thing will happen, the Potential Energy is high, and the Kinetic Energy is low. Through all of that the Mechanical Energy stays the same. 

I hope this helps. :)

Brainliest?

8 0
3 years ago
A 1500-kg car accelerates from 0 to 25 m/s in 7.0s with negligible friction and air resistance. What is the average power delive
NARA [144]

Answer:

90 hp

Explanation:

Power = work / time

P = ½ (1500 kg) (25 m/s)² / 7.0 s

P = 67,000 W

P = 90 hp

4 0
3 years ago
What's the gravity?
poizon [28]

Answer:

gravity is the force by which a planet or another body draws objects towards its Centre. the force of gravity keeps all of the planets in an orbit around the sun.

Explanation:

what is gravity made of?

gravity are made of proposed gravity parts that are made quantum particles which called gravitational anywhere there is gravitation there is gravity like on Earth in the Solar System most importantly in the minisclue infant and intervention universe .

6 0
3 years ago
Question 3
Gennadij [26K]
A. B. D. C. D, A, A, C, B, B, D, D
5 0
3 years ago
If you pull horizontally on a desk with a force of 150 N and the desk doesn't move, the friction force must be 150 N. Now if you
s344n2d4d5 [400]

Answer:

The friction force is 250 N

Explanation:

The desk is moving at constant velocity. This means that its acceleration is zero: a = 0. Newton's second law states that the resultant of the forces acting on the desk is equal to the product between mass (m) and acceleration (a):

\sum F=ma

In this case, we know that the acceleration is zero: a = 0, so also the resultant of the forces must be zero:

\sum F = 0 (1)

We are only interested in the forces acting along the horizontal direction, since it is the direction of motion. There are two forces acting in this direction:

- the pull, forward, F = 250 N

- the friction force, backward, F_f

Given (1), we have

F-F_f = 0

So the force of friction must be equal to the pull:

F=F_f = 250 N

8 0
3 years ago
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