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xenn [34]
3 years ago
6

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

is correct?
Physics
1 answer:
AleksandrR [38]3 years ago
6 0

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.

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the measure of each exterior angle of a regular pentagon is ___ the measure of each exterior angle of a regular nonagon
Cerrena [4.2K]

Answer:

(a) 72°

(b) 40°

Explanation:

PENTAGON

First, we calculate the total angles in a Pentagon using:

180(n - 2)

Where n = number of sides of the polygon, in this case, 5.

Hence, the total angle in a polygon is

180(5 - 2) = 180 * 3 = 540°

Therefore, each angle will be:

540°/5 = 108°

Because the interior angle and exterior angle form a straight line (180°), the exterior angle of a regular pentagon will be:

180 - 108 = 72°

The exterior angle of a regular Pentagon is 72°

NONAGON

First, we calculate the total angles in a Nonagon using:

180(n - 2)

Where n = number of sides of the polygon, in this case, 9.

Hence, the total angle in a polygon is

180(9 - 2) = 180 * 7 = 1260°

Therefore, each angle will be:

1260°/9 = 140°

Because the interior angle and exterior angle form a straight line (180°), the exterior angle of a regular nonagon will be:

180 - 140 = 40°

The exterior angle of a regular Nonagon is 40°

4 0
3 years ago
You are riding a bicycle. If you apply a forward force of 150 N, and you and the bicycle have a combined mass of 90 kg, what wil
bekas [8.4K]
<h3>Hello There!!</h3>

<h3><u>Given</u>,</h3>

Force(F) = 150N

Mass(m) = 90kg

<h3><u>To </u><u>Find,</u></h3>

Acceleration(a) = ?

<h3><u>We know,</u></h3>

F= m×a

150 = 90 \times  \text{a} \\  \\  \text{a} =  \frac{150}{90}  \\  \fbox{cancelling by 3} \\  \\   \text{ a}  = \cancel \frac{150}{90} \\  \\ \text{ a}  =  \frac{5}{3}  = 1.67 \text{m/s} {}^{2}

\therefore  \text{Option A= 1.67 m/s² is the correct answer}

<h3>Hope this helps</h3>
6 0
2 years ago
Science: Which statement is true about star A
Elza [17]

Answer:

no clue

Explanation:

6 0
2 years ago
The voltage across the terminals of a generator is 5.7 v when it supplies a current of 0.3 A. It becomes 5.1 V when I=0.9A. Find
snow_tiger [21]

Answer:

  • The emf of the generator is 6V
  • The internal resistance of the generator is 1 Ω

Explanation:

Given;

terminal voltage, V = 5.7 V, when the current, I = 0.3 A

terminal voltage, V = 5.1 V, when the current, I = 0.9 A

The emf of the generator is calculated as;

E = V + Ir

where;

E is the emf of the generator

r is the internal resistance

First case:

E = 5.7   + 0.3r -------- (1)

Second case:

E = 5.1 + 0.9r -------- (2)

Since the emf E, is constant in both equations, we will have the following;

5.1 + 0.9r = 5.7   + 0.3r  

collect similar terms together;

0.9r - 0.3r = 5.7 - 5.1

0.6r = 0.6

r = 0.6/0.6

r = 1 Ω

Now, determine the emf of the generator;

E = V + Ir

E = 5.1 + 0.9x1

E = 5.1 + 0.9

E = 6 V

6 0
2 years ago
One type of energy is the result of waves that travel through matter and cause particles in the matter to vibrate.Which type of
umka2103 [35]
sound energy hope this helps please give brainliest
3 0
3 years ago
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