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White raven [17]
3 years ago
8

Astronomers initially had difficulty identifying the emission lines in quasar spectra at optical wavelengths because

Physics
1 answer:
Rus_ich [418]3 years ago
6 0
No one expected violet & ultraviolet spectral lines to be shifted towards the red.
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To collect quantitative data, scientists use all of the following except _____.
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You would use all of the following except for 3. descriptive categories because, that is a qualitative observation using descriptions and not a quantitative observation using numbers.<span />
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2 years ago
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Sawyer launches his 180 kg raft on the Mississippi River by pushing on it with a force of 75N. How long must Sawyer push on the
Daniel [21]

Answer: 4.8 s

Explanation:

We have the following data:

m=180 kg the mass of the raft

F=75 N the force applied by Sawyer

V=2 m/s the raft's final speed

V_{o}=0 m/s the raft's initial speed (assuming it starts from rest)

We have to find the time t

Well, according to Newton's second law of motion we have:

F=m.a (1)

Where a is the acceleration, which can be expressed as:

a=\frac{\Delta V}{\Delta t}=\frac{V-V_{o}}{t-t_{o}} (2)

Substituting (2) in (1):

F=m\frac{V-V_{o}}{t-t_{o}} (3)

Where t_{o}=0

Isolating t from (3):

t=\frac{m(V-V_{o})}{F} (4)

t=\frac{180 kg(2 m/s-0 m/s)}{75 N}

Finally:

t=4.8 s

6 0
2 years ago
How do icebergs form
pishuonlain [190]

Answer:

They break off large ice sheets found at the North and South poles.

5 0
2 years ago
PHYSICS<br> I need help with number two!!!!
EleoNora [17]

Answer:

mgh₁ + ½mv₁² = mgh₂ + ½mv₂²

Explanation:

Initial total energy = final total energy

PE₁ + KE₁ = PE₂ + KE₂

mgh₁ + ½mv₁² = mgh₂ + ½mv₂²

7 0
3 years ago
If you use a force of 90 N to pick up a 10 pound bag of charcoal, what is the acceleration?
hjlf

Answer:

9ms^2

Explanation:

since ,Force=mass*acceleration

then, acceleration=force/mass

and, Force=90N

Mass=10pound

therefore, acceleration=90/10

=9ms^2

8 0
3 years ago
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