Electrical current is directly proportional to which of the following quantities?

True or False. Recent findings lend strong support to the theory that a black hole lies at the center of the Milky Way and of ma

Genrish500 [490]

Answer:

True

Explanation:

In 2019 was taken the first image of a supermassive black hole in the center of the galaxy M87 with the Event Horizon Telescope, which is a network of radio telescope located in different points of the Earth, with the purpose of making a telescope of the size of the Earth.

A radio telescope is an antenna that is capable to perceive the light in the radio part of the electromagnetic spectrum¹.

It is important to notice that in the picture what it can be seen is the effect that the black hole has in the nearby stars.

Key terms:

¹Electromagnetic spectrum: decomposition of light in its different wavelengths (from radio waves to gamma rays).

7 0

3 years ago

Consider a rectangular ice floe 5.00 m high, 4.00 m long, and 3.00 m wide. a) What percentage of the ice floe is below the water

artcher [175]

Answer:

(a) 92 %

(b) 6.76 %

Explanation:

length, l = 4 m, height, h = 5 m, width, w = 3 m, density of water = 1000 kg/m^3

density of ice = 920 kg/m^3, density of mercury = 13600 kg/m^3

(a) Let v be the volume of ice below water surface.

By the principle of flotation

Buoyant force = weight of ice block

Volume immersed x density of water x g = Total volume of ice block x density

of ice x g

v x 1000 x g = V x 920 x g

v / V = 0.92

% of volume immersed in water = v/V x 100 = 0.92 x 100 = 92 %

(b) Let v be the volume of ice below the mercury.

By the principle of flotation

Buoyant force = weight of ice block

Volume immersed x density of mercury x g = Total volume of ice block x

density of ice x g

v x 13600 x g = V x 920 x g

v / V = 0.0676

% of volume immersed in water = v/V x 100 = 0.0676 x 100 = 6.76 %

4 0

3 years ago

Two strings are adjusted to vibrate at exactly 202 Hz. Then the tension in one string isincreased slightly. Afterward, three bea

Semenov [28]

The concepts necessary to solve this problem are framed in the expression of string vibration frequency as well as the expression of the number of beats per second conditioned at two frequencies.

Mathematically, the frequency of the vibration of a string can be expressed as

$f = \frac{1}{2L}\sqrt{\frac{T}{\mu}}$

Where,

L = Vibrating length string

T = Tension in the string

$\mu =$ Linear mass density

At the same time we have the expression for the number of beats described as

$n = |f_1-f_2|$

Where

$f_1$ = First frequency

$f_2$ = Second frequency

From the previously given data we can directly observe that the frequency is directly proportional to the root of the mechanical Tension:

$f \propto \sqrt{T}$

If we analyze carefully we can realize that when there is an increase in the frequency ratio on the tight string it increases. Therefore, the beats will be constituted under two waves; one from the first string and the second as a residue of the tight wave, as well

$n = f_2-f_1$

$f_2 = n+f_1$

Replacing $3/s$ for n and 202Hz for $f_1,$

$f_2 = 3/s + 202Hz$

$f_2 = 3/s(\frac{1Hz}{1/s})+202Hz$

$f_2 = 206Hz$

The frequency of the tightened is 205Hz

7 0

3 years ago

The biggest reason that some fuels are considered nonrenewable

zhuklara [117]

Because many fuels are fossil fuels they take millions of years to form and the known reserves are being used much faster than the new ones being made

4 0

3 years ago

Black holes must have a mass three or more times the mass of _____.

tia_tia [17]

The answer is <span>d. the sun</span>

7 0

3 years ago

Read 2 more answers