Respond to the following based on your reading.

If a black hole itself emits no radiation, what evidence do astronomers and physicists today have that the theory of black holes

AleksandrR [38]

Answer:

Einstein's general theory of relativity is the theory behind black holes has been tested with a wide range of experiments of which all confirm the predictions the theory makes. We cannot see black holes phenomena inside the event horizon, we do observe things outside this limit.

Black holes in binary star systems leave signs of their presence on neighboring star thats detected and the signs include X-ray emissions, accretion disks, and large orbit perturbations.

this is the evidence that astronomers and physicists have to show that the theory about black holes is correct.

6 0

3 years ago

If the car is traveling at a velocity of 15 m/s, what is the approximate centripetal acceleration of the car?.

BaLLatris [955]

The vehicle's centripetal acceleration is equal to 22.5m/s²

Radius, r = 10 meter

Speed, V = 15 m/s

To ascertain the car's centripetal acceleration

A(c) = V²/R

We obtain the following when we enter the formula's parameters:

A(c) = 152/10

A(c) = 225/10

A(c) = 22.5m/s²

<h3>What is Centripetal acceleration ?</h3>

When an item moves in a circular route, one of its motion characteristics is centripetal acceleration. Any motion in a circle with an acceleration vector pointing in the direction of the circle's centre is referred to as centripetal acceleration.

Centripetal forces cause accelerations at the centripetal axis. With the exception of the Earth's rotation around the Sun, any satellite's circular motion around a celestial body is brought on by the centripetal force produced by their mutual gravitational pull.

Hence, Centripetal acceleration is

22.5 m/s²

Learn more about Centripetal acceleration here:

brainly.com/question/79801

#SPJ4

7 0

1 year ago

The circumference of a sphere was measured to be

professor190 [17]

To solve this problem we will apply the concepts related to the calculation of the surface, volume and error through the differentiation of the formulas given for the calculation of these values in a circle. Our values given at the beginning are

$\phi = 76cm$

$Error (dr) = 0.5cm$

The radius then would be

$\phi = 2\pi r \\76cm = 2\pi r\\r = \frac{38}{\pi} cm$

And

$\frac{d\phi}{dr} = 2\pi \\d\phi = 2\pi dr \\0.5 = 2\pi dr$

PART A ) For the Surface Area we have that,

$A = 4\pi r^2 \\A = 4\pi (\frac{38}{\pi})^2\\A = \frac{5776}{\pi}$

Deriving we have that the change in the Area is equivalent to the maximum error, therefore

$\frac{dA}{dr} = 4\pi (2r) \\dA = 4r (2\pi dr)$

Maximum error:

$dA = 4(\frac{38}{\pi})(0.5)$

$dA = \frac{76}{\pi}cm^2$

The relative error is that between the value of the Area and the maximum error, therefore:

$\frac{dA}{A} = \frac{\frac{76}{\pi}}{\frac{5776}{\pi}}$

$\frac{dA}{A} = 0.01315 = 1.31\%$

PART B) For the volume we repeat the same process but now with the formula for the calculation of the volume in a sphere, so

$V = \frac{4}{3} \pi r^3$

$V = \frac{4}{3} \pi (\frac{38}{\pi})^3$

$V = \frac{219488}{3\pi^2}$

Therefore the Maximum Error would be,

$\frac{dV}{dr} = \frac{4}{3} 3\pi r^2$

$dV = 2r^2 (2\pi dr)$

$dV = 4r^2 (\pi dr)$

Replacing the value for the radius

$dV = 4(\frac{38}{\pi})^2(0.5)$

$dV = \frac{2888}{\pi^2} cm^3$

And the relative Error

$\frac{dV}{V} = \frac{ \frac{2888}{\pi^2}}{ \frac{219488}{3\pi^2} }$

$\frac{dV}{V} = 0.03947$

$\frac{dV}{V} = 3.947\%$

3 0

3 years ago

What is the required force to bring a 1550 kg vehicle moving at 32 m/s to a stop in a distance of 45 m?

Vilka [71]

The answer is 9 i think.

8 0

3 years ago

The first antiparticle, the positron or antielectron, was discovered in 1932. It had been predicted by Paul Dirac in 1928, thoug

Taya2010 [7]

Answer:

Energy of Photon = 4.091 MeV

Explanation:

From the conservation of energy principle, we know that total energy of the system must remain conserved. So, the energy or particles before collision must be equal to the energy of photons after collision.

K.E OF electron + Rest Energy of electron + K.E of positron + Rest Energy of positron = 2(Energy of Photon)

where,

K.E OF electron = 3.58 MeV

Rest Energy of electron = 0.511 MeV

Rest Energy of positron = 0.511 MeV

K.E OF positron = 3.58 MeV

Energy of Photon = ?

Therefore,

3.58 MeV + 0.511 MeV + 3.58 MeV + 0.511 MeV = 2(Energy of Photon)

Energy of Photon = 8.182 MeV/2

<u>Energy of Photon = 4.091 MeV</u>

8 0

3 years ago