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Natasha2012 [34]
2 years ago
7

Which of the following is an example of a chemical change?

Physics
1 answer:
tankabanditka [31]2 years ago
3 0

b. burning paper

hope it helps

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What would you say to a friend who made this statement, “The visible-light spectrum of the Sun shows weak hydrogen lines and str
Oliga [24]

Explanation:

spectral lines or signatures of elements depend on temperature, the temperature of the sun is about 5800 K.

at this temperature most calcium atoms are excited to higher energy states than hydrogen atoms and this means that calcium atoms are gonna have more signatures than the atoms of hydrogen.

the statement that the sun shows weak hyrogen lines and strong calcium line is wrong because at the sun's temperature most of the hydrogen atoms are in lower energy states while calcium atoms are in higher energy states hence calcium has more or ''strong'' lines than hydrogen.

8 0
3 years ago
Which of the following is NOT true regarding the far side of the moon:
frutty [35]
It contains no large maria
8 0
3 years ago
How does Sonar work?i will mark brainliest pls help
Fittoniya [83]
I don't like the wording of any of the choices on the list.

SONAR generates a short pulse of sound, like a 'peep' or a 'ping',
focused in one direction.  If there's a solid object in that direction,
then some of the sound that hits it gets reflected back, toward the
source.  The source listens to hear if any of the sound that it sent
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the time it took for the sound to go out and come back.  That tells
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RADAR works exactly the same way, except RADAR uses radio waves. 


5 0
3 years ago
A spherical weather balloon is filled with hydrogen until its radius is 4.40 m. Its total mass including the instruments it carr
ipn [44]

Answer:

4515.49484 N

4329.10484 N

Explanation:

r = Radius of balloon = 4.4 m

m = Mass of balloon with instruments = 19 kg

g = Acceleration due to gravity = 9.81 m/s²

Volume of balloon

v=\frac{4}{3}\pi r^3\\\Rightarrow v=\frac{4}{3}\pi 4.4^3\\\Rightarrow v=356.8179\ m^3

The Buoyant force = Weight of the air displaced

F=\rho vg\\\Rightarrow F=1.29\times 356.8179\times 9.81\\\Rightarrow F=4515.49484\ N

The buoyant force acting on the balloon is 4515.49484 N

Net force on the balloon

F_n=F-W\\\Rightarrow F_n=4515.49484-19\times 9.81\\\Rightarrow F_n=4329.10484\ N

The net force on the balloon is given by 4329.10484 N

As the balloon goes up the pressure outside reduces as the density of air decreases while the air pressure inside the balloon is high hence, the radius of the balloon tend to increase as it rises to higher altitude.

5 0
2 years ago
If a magnet is broken into two pieces, what happens to the magnetic poles?
Nostrana [21]

Answer:

The second is correct.

Explanation:

Try with a magnet and experiment. You'll find out

6 0
2 years ago
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