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3 years ago

What is the average density of a neutron star that has the same mass as the sun but a radius of only 20.0 km?

Physics

1 answer:

IrinaK [193]3 years ago

4 0

Answer: $5.935(10)^{13}g/cm^{3}}$

Explanation:

Density is a characteristic property bodies and materials, and is defined as the relationship between the mass $m$ and the volume $V$ , as shown below:

$D=\frac{m}{V}$ (1)

In the case of the neutron star, we know it has the same mass as the Sun:

$m=1.989(10)^{30}kg$

And its radius is $r=20km$

On the other hand, if we assume this neutron star has a spherical shape, its volume can be calculated by the following formula:

$V=V_{sphere}=\frac{4}{3}\pir^{3}$ (2)

$V=\frac{4}{3}\pi(20km)^{3}$ (3)

$V=33510.321km^{3}$ (4)

Substituting (4) in (1):

$D=\frac{1.989(10)^{30}kg}{33510.321km^{3}}$ (5)

Finally:

$D=5.935(10)^{25}kg/km^{3}}=5.935(10)^{13}g/cm^{3}}$

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A motorboat sets out for open sea. From home it travels 5 km due East, then heads [N35E] at 2 m/s for 90 minutes. After a break,

geniusboy [140]

The distance of the motorboat relative to the home, which travels in various directions, is 3.07 km.

<h3>What is relative velocity?</h3>

Relative velocity is a velocity of an object which is in respect to another observer, or it is a ratio of change in the position of a point to time with respect to another observer.

Given: Travel in East direction ( $d_{E}$ )= 5 km,

velocity in N35E(v) = 2 m / s, time taken(t) = 90 min = 5400 seconds,
Displacement in south ( $D_S}$ ) = 6.5 km

Firstly, find the displacement in N35E so

Displacement = Velocity × time,

$d_{NE}$ = 2 × 5400 = 10800 meters or 10.8 km

Now by using Pythagoras' theorem
We can calculate the return displacement in the south direction( $d_{S}$ ),

$d_{S}$ = $\sqrt{d^{2} _{NE}- d^{2} _{E } }$
$d_{S}$ = $\sqrt{10.8^{2}-5^{2} }$

$d_{S}$ = 9.57 km

Therefore, the distance of the boat from the home (D) = $d_S}$ - $D_S}$

D = 9.57 - 6.5;

D = 3.07 Km

To know more about Relative velocity:

brainly.com/question/19260269

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1 year ago

A gas in a cylinder is held at a constant pressure of 1.80 * 105 Pa and is cooled and compressed from 1.70 m3 to 1.20 m3. The in

Lilit [14]

Answer:

The work done is $W=-0.9*10^5J$ and it is negative because the exterior is doing work on the gas.

The value of the heat flow is $Q=2.3*10^5J$ and is directed out of the gas, as this is being cooled and compressed.

Explanation:

The work done by the gas can be written as

$W=\int\limits^ {V_{c}}_{V_{h}}{P}\, dV$

and all the data is given in the problem, so

$W=P(V_{c}-V_{h})=-0.9*10^5J$

is the work necessary to compress the gas in the cylinder, wich is negative because the exterior is doing work on the gas.

Now, from first law of thermodynamics, we have that

$\Delta U=Q+W$

<em>where $\Delta U$ is the internal energy difference, $W$ is the calculated work, and $Q$ is the heat flow that we wish to know</em>, then

$Q=\Delta U-W=1.4*10^5J+0.9*10^5J=2.3*10^5J$

And the direction of the heat flow is outside of the gas, as it is being cooled and compressed.

Finally, it doesn't matter whether the gas is ideal or not, because we never use the Ideal Gas hypotesis, that $PV=nRT$ , and $P$ is constant.

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3 years ago

2075 Set A Q.No. 106 A Carnot engine has 40% efficiency with a sink at 10°C. By how many degrees should the temperature of the s

Anni [7]

Answer:

Explanation:

Efficiency of a Carnot engine = 1 – (T2/T1) ;

where T1 = source temperature and T2 = sink temperature

T2 = 10⁰C = 273+10 = 283K

The initial efficiency = 40%

So 0.4 = 1 - (283/Initial T1)

Initial T1 = 283/(1-0.4) = 471.67 K

To raise efficiency to 65%

0.65 = 1 - (283/Increased T1)

Increased T1 = 283/(1-0.65) = 808.57 K

The source temperature must be increased by 808.57 - 471.67 = 336.9 K or 336.9°C.

8 0

3 years ago

Read 2 more answers

Could a mixture be made up of only elements and no compounds. if so explain

Irina18 [472]

I racked my brain for almost 10 minutes, until suddenly,
it hit me !

You're breathing one right now ! So am I .

Air is a mixture of a lot of elements.
Nitrogen, Oxygen, and Argon account for 99.964 percent.

The other 0.036 percent is mainly Neon, Helium, Krypton,
and Hydrogen ... more elements.

Then there are Carbon Dioxide and water vapor.
Yes, those are compounds. But together, they add up
to very little of the air we breathe, and if both of them
suddenly disappeared, we would hardly notice it.

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3 years ago

In each case, lifting or pushing, why must you exert a force to move the object? Q1-2: How much more effort is required to lift

musickatia [10]

Answer:

Newton's first law applies. An object at rest will stay that way until a force is applied.
Any amount of effort can be applied to any amount of mass (in the ideal case). The question is not sufficiently specific.

Explanation:

A force is required to move an object because the object will stay at rest until a force is applied.

The effort required to lift or push two masses instead of one depends on the desired effect. For the same kinetic energy, no more effort is required. For the same momentum, half the effort is required for two masses. For the same velocity, double the effort is required.

4 0

3 years ago