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3 years ago

What does the galaxy made of ?

1 answer:

4 0

Galaxies are sprawling systems of dust, gas, dark matter, and anywhere from a million to a trillion stars that are held together by gravity. Nearly all large galaxies are thought to also contain supermassive black holes at their centers.

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A spherical capacitor is formed from two concentric spherical conducting shells separated by vacuum. The inner sphere has a radi

Svetlanka [38]

Answer: a) 73.41 10^-12 F; b)4.83* 10^3 N/C; c) 3.66 *10^3 N/C

Explanation: To solve this problem we have to consider the following: The Capacity= Charge/Potential Difference

As we know the capacity is value that depend on the geometry of the capacitor, in our case two concentric spheres.

So Potential Difference between the spheres is given by:

ΔV=- $\int\limits^a_b {E} \, dx$

Where E = k*Q/ r^2

so we have $\int\limits^a_b {K+Q1/r} \, dr$

then

Vb-Va=k*Q(1/b-1/a)=kQ (ab/b-a)

Finally using C=Q/ΔV=ab/(k(b-a))

To caclulate the electric firld we first obtain the charge

Q=ΔV*C=120 V*73.41 10^-12 F=8.8 10^-9 C

so E=KQ/r^2 for both values of r

r=12.8 cm ( in meters)

r2=14.7 cm

E(r1)=4.83* 10^3 N/C

E(r2)=3.66 *10^3 N/C

8 0

3 years ago

Two parallel plates have equal and opposite charges. When the space between the plates is evacuated, the electric field is E= 3.

svetlana [45]

Explanation:

The given data is as follows.

Electric field between plates without dielectric, $E_{1} = 3.50 \times 10^{5} V/m$

Electric field between the plates with dielectric, $E_{2} = 2.40 \times 10^{5} V/m$ .

Permittivity of free space, $\epsilon_{o}$ = $8.85 \times 10^{-12} C^{2}/Nm^{2}$

Now, we will determine the charge density as follows.

$\sigma_{i} = \epsilon_{o}(E_{1} - E_{2})$

= $8.85 \times 10^{-12} \times (3.50 \times 10^{5} - 2.40 \times 10^{5})$

= $9.735 \times 10^{-7} C/m^{2}$

Thus, we can conclude that the charge density on each surface of the dielectric is $9.735 \times 10^{-7} C/m^{2}$ .

6 0

3 years ago

Danny Diver weighs 500 N and steps off a diving board 10 m above the water. Danny hits the water with kinetic energy of

Morgarella [4.7K]

Answer:

Danny hits the water with kinetic energy of 5000 J.

Explanation:

Given that,

The Weight of Danny Diver,

F = 500 N

m*g= 500 N

He steps off a diving board 10 m above the water.

h=10 m

when Danny diver hits water he generates the kinetic energy.

We need to find the kinetic energy of the water.

Let kinetic energy is K.

K = m*g*h

Where g is acceleration due to gravity.

that g= 9.8 m/s^2

now substituting the values in above equation

K= (500) * 10

K= 5000 J

Hence,

he hits the water with kinetic energy of 5000 J.

Learn more about Kinetic energy here:

<u>brainly.com/question/15587458</u>

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#SPJ4

7 0

2 years ago

Object's velocity change

marshall27 [118]

the definition of acceleration in kinematics, allows to find that the correct answer is:

2. speed up ( acceleration)

The kinematics study the movement of the body, the acceleration is defined as the change of the speed by the time in the interval

a = Δv / t

Where the bold letters indicate vectors, a is the acceleration, v the velocity and t the time

Analyzing this expression we see that for there to be a change in velocity, there must be an acceleration of the body.

Let's analyze the different claims

1. True. If it is stopped and you start to move there is an acceleration, therefore there is a change in speed, but after you are moving the acceleration becomes zero and there is no change in speed

2. True. Whenever there is acceleration there is a change in speed

3. False. Moving slowly does not change the acceleration, therefore there is no change in speed

4. True. If you are moving and you stop at this moment there is an acceleration, therefore there is a change in speed, but after being stopped the acceleration is zero and there is no change in speed

5. False. If you change the direction at the instant of change there is an acceleration but after you go in the opposite direction there is not acceleration therefore there is no change in speed.

In conclusion using the definition of acceleration in kinematics, we can find the answer the condition for a change in velocity, the correct statement is:

2. speed up ( acceleration)

Learn more here: brainly.com/question/5063616

3 0

2 years ago

The slope of the line on a speed-time graph tells the speed.

iren2701 [21]

From the choices provided, the better answer is ' T ' .

8 0

3 years ago

What does the galaxy made of ?​

What does the galaxy made of ?