1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Gekata [30.6K]
3 years ago
10

Because of interstellar dust, astronomers can see at most about 5 kpc into the disk of the galaxy at visual wavelengths. What pe

rcentage of the galactic disk does that include? (Hint: Consider the area of the entire disk versus the area visible from Earth. The diameter of the Milky Way Galaxy is approximately 25 kpc.)
Physics
1 answer:
NNADVOKAT [17]3 years ago
5 0

Answer:

96%

Explanation

Let A the total area of the galaxy, is modeled as a disc:

A = πR^2 = π (25 kpc)^2

And let a be the area that astronomers are able to see:

a = πr^2 = π(5 kpc)^2

The percentage that can be seen is equal to 100 times the ratio of the areas, of the galaxy and the "visible" part:

P = 100 a/A = (5/25)^2 = 100/25 = 4%

Therefore, the percentage of the galaxy not included, i.e. not seen is:

(100-4)% = 96%

You might be interested in
Describe, using the relevant physics, how moving a magnet near a [ 1 2 ] solenoid induces a voltage across it. How does the spee
Svetllana [295]

Answer:

Explanation:

Moving a magnet might cause a change in the magnetic field going through the solenoid. Whether or not it will change depends on the movement.

According to Faraday's law of induction a voltage is induced in a coil by a change in the magnetic flux. Magnetic flux is defined as the dot product of the magnetic field (a vector field) by the area enclosed by a loop of the coil.

\Phi B = -\int{B} \, dA

The voltage is induced by the variation of the magnetic flux:

\epsilon = -N * \frac{d \Phi B}{dt}

Where

ε: electromotive fore

N: number of turns in the coil

ΦB: magnetic flux

Moving the magnet faster would increase the rare of change of the magnetic flux, resulting in higher induced voltage.

Turning the magnet upside down would invert the direction of the magnetic field, reversing the voltage induced.

5 0
3 years ago
Help with 5-10 please
Zina [86]

Answer:

explained in attachment

Explanation:

explained in attachment

Download pdf
5 0
3 years ago
Which of the following statements describes a battery?
LiRa [457]

Answer:

The negative electrode of a battery has an excess of positive charge

Explanation:

This is because in every battery, there is a negative electrode ( cathode ) and only positive charge is deposited on it.

For other statements:

Batteries donot store electric charge but they store chemical energy

Some batteries donot use metals for the flow of electrons, but some use hydrogen gas at a pressure of 1 atmosphere.

8 0
3 years ago
What quantity is the rate of change of velocity? Displacement Acceleration Final velocity
MariettaO [177]

Answer:

Acceleration

Explanation:

The quantity of the rate of change of velocity is termed the acceleration of the body.

Acceleration is the rate of change of velocity with time;

  A  = \frac{v - u}{t}  

A is the acceleration

v is the final velocity

u is the initial velocity

t is the time taken

 

7 0
3 years ago
Suppose you are standing at the earth's geographic north magnetic pole, the place on the earth's surface that compasses point to
Brut [27]

Answer:

It would point up.

Explanation:

Since I am at the earth's geographic north magnetic pole, the place on the earth's surface that compasses point toward, the north pole of the compass would also point towards the earth's geographic north magnetic pole, since all other compasses point toward there.

Since the compass is free to swivel in any direction, the compass would point up, since it is at the earth's geographic north magnetic pole, the place on the earth's surface that compasses point toward.

So, the compass would point up.

7 0
2 years ago
Other questions:
  • Titin is a spring-shaped elastic protein that attaches to the thick filament and anchors it to the Z-discs of a sarcomere. If ti
    15·1 answer
  • A soccer ball is released from rest at the top of a grassy incline. After 8.6 seconds, the ball travels 87 meters and 1.0 s afte
    8·1 answer
  • TRUE OR FALSE: ancient swamp plants slowly decayed and turned into peat, the first step in making coal.
    5·2 answers
  • A 230 kg steel crate is being pushed along a cement floor. The force of friction is 480 N to the left and the applied force is 1
    11·2 answers
  • A mother pushes a baby stroller 10 meters by applying 40 newtons of force. How much work was done?
    9·2 answers
  • An unfortunate bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of t
    11·1 answer
  • A roller coaster car with a mass of 17,690 kg is moving at a speed of 5 m/s over a hill that is 87.4 m above the
    13·1 answer
  • 3.
    8·1 answer
  • The materials in the pictures below trap air. They act as as good insulator against...
    14·2 answers
  • During a ______ Moon phase, the side of the Moon facing Earth isn't reflecting any sunlight from the Sun.
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!