According to Einstein's theory of relativity, a black hole is a "singularity" that consists of a region of the space in which the density of matter tends to infinity. In consequence, this huge massive body has a gravitational pull so strong that not even light can escape from it.
In addition, "the surface" of a black hole is called the event horizon, which is the border of space-time in which the events on one side of it can not affect an observer on the other side.
In other words, at this border also called "point of no return", nothing can escape (not even light) and no event that occurs within it can be seen from outside.
In this sense, and according to the relativity, it is possible to determine where a black hole is if it is "observed" an enormous amount of energy released. So, in accordance to this, galaxies like ours must have a black hole in its center.
On the other hand, the elliptical galaxy Mesier 87 (also called Virgo A, but from now on M87) was showing the above described behaviour, with enormous jets of high-energy particles shooting away from its vicinity . This was imaged by the Hubble Space Telescope years ago; that is why astronemers were hypothesizing about the existence of a massive black hole there.
Well now, on April, 10th 2019 this was demonstrated with the publication of the image, for the first time, of the event horizon of the black hole in M87. This is the first time in human history a picture of a black hole is taken.
This was done by the huge effort of diverse scientist and by the syncronization of eight radio telescopes scattered across the Earth (located at: Hawaii, Spain, Chile, Mexico, Arizona and the South Pole), which took the same point of the sky at the same time.
Several paper clips dangle from the north pole of a magnet. The induced pole in the bottom of the lowermost paper clip is a
A) north pole.
B) south pole.
C) north or south pole - no difference really.
I wanna say it’s B.
Why do astronomers think that the milky way is a spiral galaxy?
1) When you look toward the Galactic Center with your eye, you see a long, thin strip. This suggests a disk seen edge-on, rather than a ellipsoid or another shape. We can also detect the bulge at the center. Since we see spiral galaxies which are disks with central bulges, this is a bit of a top.
Final answer:
Astronomers believe the Milky Way is a spiral galaxy because its rotational motion, gas, color, and dust are characteristics of spiral galaxies, and it matches the observable structures of other known spiral galaxies. Our position within one of its spiral arms helps us observe these features. The differential rotation of the Milky Way creates and maintains the spiral arm structure over time.
Explanation:
Astronomers conclude that the Milky Way is a spiral galaxy for multiple reasons. The observable band of light from Earth, known as the Milky Way, is the disk of our galaxy which exhibits the characteristics of a typical spiral galaxy. When observing the velocity of stars and gas, we see rotational motion typical of spiral galaxies. Moreover, the presence of gas, distinctive colors, and dust within our galaxy align with those found in other known spiral galaxies.
Our Solar System is situated within one of these spiral arms, giving us a vantage point from which we observe most of the stars. To better understand the structure of the Milky Way, astronomers compare it to visible spiral galaxies, such as the Andromeda galaxy. These comparisons have been invaluable for grasping the Milky Way's properties.
One of the Milky Way’s defining features is its differential rotation, which causes its material to stretch into the distinct spiral arms we theorize it has. Despite this differential rotation, which one might expect would wind the arms tighter over billions of years, the arms maintain their spiral structure, suggesting that there are additional dynamics at play to keep them from winding up too tightly.
An ice cube of mass 50.0 g can slide without friction up and down a 25.0 degree slope. The ice cube is pressed against a spring at the bottom of the slope, compressing the spring 0.100 m . The spring constant is 25.0 N/m . When the ice cube is released, how far will it travel up the slope before reversing direction?Identify the initial and final gravitational potential energies.Enter your answers, separated by a comma, in terms of some or all of the variables m, k, x, d, θ, and the acceleration due to gravity, g.Identify the initial and final elastic potential energies.Enter your answers, separated by a comma, in terms of some or all of the variables m, k, x, d, θ, and the acceleration due to gravity, g.
The initial gravitational potential energy of the ice cube is zero, and the final gravitational potential energy is mgxsin(θ). The initial elastic potential energy of the spring is 0.125 J, and the final elastic potential energy is zero.
Explanation:First, let's calculate the initial gravitational potential energy of the ice cube. The potential energy is given by the formula PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height. Since the ice cube is at the bottom of the slope, the height h is zero. Therefore, the initial gravitational potential energy is 0.
Next, let's calculate the final gravitational potential energy of the ice cube. When the ice cube reaches the maximum height before reversing direction, its height h is given by h = d * sin(θ), where d is the distance traveled up the slope and θ is the angle of the slope. Plugging in the values, we get h = x * sin(θ). Therefore, the final gravitational potential energy is mgh = mgxsin(θ).
The initial elastic potential energy of the spring is given by the formula PE = 0.5kx^2, where k is the spring constant and x is the compression distance. Plugging in the values, we get PE = 0.5 * 25.0 * (0.100)^2 = 0.125 J. The final elastic potential energy is zero because the spring is fully extended when the ice cube reaches the maximum height.
Electrons in an atom make up most of the _________ of the atom, while the protons and neutrons make up nearly all of the __________ of the atom.
Answer:
volume;mass
Explanation:
Answer:
Electrons in an atom make up most of the volume of the atom, while the protons and neutrons make up nearly all of the mass of the atom.
Explanation:
Most of the mass of an atom comes from its nucleus, in which protons and neutrons are found, both of these particles have approximately the same mass.
The atom is also composed of electrons rotating in orbitals around the nucleus, and they have little mass compared to a proton or neutron. But despite being much lighter than the particles in the nucleus, the electron cloud occupies most of the space or volume of the atom.
A rubber ball and a lump of clay have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the wall. Which one of these objects experiences the greater momentum change?
Answer:
The ball experiences the greater momentum change
Explanation:
The momentum change of each object is given by:
[tex]\Delta p = m \Delta v= m (v-u)[/tex]
where
m is the mass of the object
v is the final velocity
u is the initial velocity
Both objects have same mass m and same initial velocity u. So we have:
- For the ball, the final velocity is
[tex]v=-u[/tex]
Since it bounces back (so, opposite direction --> negative sign) with same speed (so, the magnitude of the final velocity is still u). So the change in momentum is
[tex]\Delta p=m(v-u)=m((-u)-u)=-2mu[/tex]
- For the clay, the final velocity is
[tex]v=0[/tex]
since it sticks to the wall. So, the change in momentum is
[tex]\Delta p = m(v-u)=m(0-u)=-mu[/tex]
So we see that the greater momentum change (in magnitude) is experienced by the ball.
The ball has more momentum as compared to clay due to its higher motion.
Which have more momentum?The ball experiences the greater momentum change because it bouce back by the wall with the same amount of force while on the other hand, the clay sticks to the wall and stopped its motion
So we can conclude that the ball has more momentum as compared to clay due to its higher motion.
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Pls help! Urgent and giving brainliest!
Arrange the letters to show the path of the light ray as it travels from the object to the viewers eye.
A B C D E
Answer:
DCEBA
Explanation:
You would like a pendulum that swings back and forth once every 2 seconds, but the one you have swings once every 1.9 seconds. Which of the following should you do to adjust it so that it has the desired period?Remove some mass from the pendulum.Make the pendulum slightly shorter.Add more mass to the pendulum.Make the pendulum slightly longer.
Your pendulum does a complete swing in 1.9 seconds. You want to SLOW IT DOWN so it takes 2.0 seconds.
Longer pendulums swing slower.
You need to make your pendulum slightly longer.
If your pendulum is hanging by a thread or a thin string, then its speed doesn't depend at all on the weight at the bottom. You can add weight or cut some off, and it won't change the speed a bit.
Final answer:
To make a pendulum swing with a period of 2 seconds instead of 1.9 seconds, the length of the pendulum should be increased.
Explanation:
The subject of this question is Physics, specifically concerning mechanics and the operation of a simple pendulum. To achieve the desired period of 2 seconds per swing for your pendulum, which currently swings once every 1.9 seconds, you should make the pendulum slightly longer. The period of a simple pendulum is determined by the formula T = 2π√(L/g), where T is the period, L is the length, and g is the acceleration due to gravity. Since the period is proportional to the square root of the length, and you wish to increase the period, you should increase L, meaning the length of the pendulum must be extended. Adding mass, removing mass, or shortening the length of the pendulum would not give you the desired period.
50 POINTS! If the moon were twice as massive but twice as far from Earth, high tides on Earth would be – (think of it’s force)
a. higher
b. lower
c. no different
The answer would be C. If its twice as massive, AND twice as far, nothing would really change.
If the moon were twice as massive but twice as far from Earth, high tides on Earth would be lower.
Answer: Option B
Explanation:
The occurrence of high tides on Earth is due to the gravitational force of moon acting on the sea water. So the gravitational force of moon during full moon day will be maximum as the distance between Earth and Moon will be minimum during this time and thus the moon’s gravity will be pulling the sea water towards itself leading to the formation of high tides.
As the high tides are formed due to the gravitational force acting between moon and Earth, the mathematical representation will be
[tex]F=\frac{G M_{\text {moon }} M_{\text {Earth}}}{d^{2}}[/tex]
Let the F be the normal gravitational force acting between moon and Earth with [tex]M_{\text {moon }}[/tex] and [tex]M_{\text {earth }}[/tex] as the mass of moon and Earth, respectively and d be the distance of separation of moon from Earth.
Now if we consider the special case given here where the mass of moon is doubled and also the distance of separation of moon from the earth is also doubled. So the new gravitational force with the parameters and comparing we get
[tex]F^{\prime}=\frac{G M_{\text {moon }}^{\prime} M_{\text {earth }}}{d^{\prime 2}}[/tex]
[tex]F^{\prime}=\frac{2 \times G \times M_{\text {moon}} \times M_{\text {earth}}}{4 d^{2}}[/tex]
[tex]F^{\prime}=\frac{1}{2} F[/tex]
So as the gravitational force between Earth and moon will be reduced to half on doubling the distance of separation as well as mass of the moon, the occurrence of high tides will be lower with the given conditions.
Trying to escape his pursuers, a secret agent skis off a slope inclined at 30° below the horizontal at 55 km/h. to survive and land on the snow 100 m below, he must clear a gorge 43 m wide. does he make it? ignore air resistance.
The agent made it since the range of his motion is greater than the width of the gorge.
The given parameters;
inclination of the slope, Ф = 30°velocity of the agent, v = 55 km/h vertical distance below the snow, h = 100 mwidth of the gorge the agent must cross, w = 43 mAssume downward motion to be negative.
The initial vertical component of the velocity in m/s;
[tex]v_0_y = v_0 \times sin(30)\\\\v_o_y = - 55 \ km/h \times sin(30) = -27.5 \ km/h = -7.64 \ m/s[/tex]
Determine the final vertical velocity of the agent;
[tex]v_y_f^2 = v_0_y^2 - 2gh\\\\v_y_f^2 = (-7.64)^2 - 2(9.8)(-100)\\\\v_y_f^2 = 2018.37\\\\v_y_f = \sqrt{2018.37} \\\\v_y_f = -44.93 \ m/s[/tex]
Determine the time of motion;
[tex]v_y_f = v_0y - gt\\\\-44.93 = -7.64 - 9.8t\\\\9.8t = 44.93 - 7.64\\\\9.8t = 37.29\\\\t = \frac{37.29}{9.8} = 3.81 \ s[/tex]
Determine the horizontal component of the initial velocity;
[tex]v_0_x = v_0 \times cos(\theta)\\\\v_0_x = 55 \ km/h \times cos(30) = 47.63 \ km/h = 13.2 \ m/s[/tex]
Determine the range of the of the agent's motion;
[tex]X = v_0_x \times t\\\\X = 13.2\ m/s \times 3.81 \ s\\\\X = 50.3 \ m[/tex]
Thus, the agent made it since the range of his motion is greater than the width of the gorge.
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Using the principles of projectile motion, we can determine that the secret agent will be able to clear the gorge and make it safely across. The agent's horizontal distance covered is 76.09 m, which is greater than the width of the gorge (43 m).
Explanation:To determine if the secret agent can make it across the gorge, we need to analyze his motion using the principles of projectile motion. Since the slope is inclined at 30° below the horizontal, we can break down the velocity into horizontal and vertical components. The horizontal component remains constant, while the vertical component changes due to the acceleration due to gravity. We can use the kinematic equations to determine the time it takes for the agent to reach the other side of the gorge. If the time is less than the time it takes for the agent to fall vertically, then he will clear the gorge and land safely on the snow.
Given that the agent skis off the slope at a speed of 55 km/h, we first need to convert this to m/s. 55 km/h is equal to 15.28 m/s. The horizontal component of the velocity remains constant at 15.28 m/s. We can determine the vertical component by multiplying the speed by the sine of the angle (30°). The vertical component is therefore 7.64 m/s. Using the equation d = v*t + 0.5*a*t^2, we can solve for time using the vertical component and the vertical distance of 100 m. Plugging in the values, we get:
100 = 7.64*t + 0.5*(-9.8)*t^2
This equation simplifies to:
4.9*t^2 + 7.64*t - 100 = 0
Solving for t, we find two possible values, t = -4.22 s and t = 4.98 s. Since time cannot be negative, we discard the negative value, leaving us with t = 4.98 s. Now we need to determine the horizontal distance the agent will travel during this time. We can use the equation d = v*t, plugging in the horizontal velocity and time:
d = 15.28 m/s * 4.98 s = 76.09 m
The horizontal distance covered by the agent is 76.09 m. Since the gorge is 43 m wide, the agent will be able to clear the gorge and make it across safely. Therefore, the secret agent does make it across the gorge.
A projectile is launched with a momentum of 200 kg •m/s and 1000 j of kinetic energy. What is the mass of the projectile?
Answer:
0.1 kg
Explanation:
The kinetic energy of an object is given by:
[tex]K=\frac{1}{2}mv^2[/tex]
where
m is the mass of the object
v is the speed of the object
The momentum of an object is given by
[tex]p=mv[/tex]
which is the product of mass and speed.
We can combine the two equations to get an expression that relates the kinetic energy K to the momentum p:
[tex]K=\frac{1}{2}m(\frac{p}{m})^2=\frac{p^2}{2m}[/tex]
In this problem, we know
[tex]K=1000 J[/tex] is the kinetic energy
[tex]p=200 kg m/s[/tex]
So we can solve the formula for m to find the mass of the projectile:
[tex]m=\frac{p^2}{2K}=\frac{(200 kg m/s)^2}{2(1000 J)}=20 kg[/tex]
The mass of the projectile object that has a kinetic energy of 1000 J and momentum of 200 kgm/s is 20 kg.
What is kinetic energy?When a body of mass (m) and moving with the velocity (u) then the body possesses the energy and this energy is called kinetic energy.
A projectile is launched with a momentum of 200 kg m/s and 1000 J of kinetic energy.
We know that the equation of kinetic energy is given by
[tex]\rm KE = \dfrac{1}{2} mu^2[/tex]...1
We know the momentum is given by
[tex]\rm P = mu\\\\u = \dfrac{p}{m}[/tex]..2
From equations 1 and 2, we have
[tex]\rm KE = \dfrac{1}{2} m(\dfrac{P}{m})^2\\\\KE = \dfrac{1}{2m} (P)^2\\\\m \ \ = \dfrac{P^2}{2*KE}[/tex]
Put the value of kinetic energy (KE) and momentum (P), we have
[tex]\rm m = \dfrac{P^2}{2*KE}\\\\\\m = \dfrac{200^2}{2*1000}\\\\\\m = \dfrac{40000}{2000}\\\\\\m = 20[/tex]
The mass of the projectile object is 20 kg.
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A device experiences a voltage drop of 5.0 V across it while a current of 10.0 mA flows through it. How much power does it dissipate? Show all work and include units of measure.
Answer:
0.05 W
Explanation:
The power dissipated by a device can be written as
[tex]P=VI[/tex]
where
P is the power dissipated
V is the voltage drop on the device
I is the current flowing through the device
In this problem, we have
V = 5.0 V is the voltage drop across the device
I = 10.0 mA = 0.01 A is the current through it
By applying the formula, we find the power dissipated:
[tex]P=(5.0 V)(0.01 A)=0.05 W[/tex]
The red light emitted by a helium–neon laser has a wavelength of 632.8 nm. What is the frequency of the light waves?
f = 4.74 × 10 ^14 Hz
hope this helps:)
The frequency of the red light waves emitted by a helium–neon laser is 4.74 × 10^14 Hartz.
What is frequency?In physics, frequency is the number of waves that pass a fixed point in a unit of time as well as the number of cycles or vibrations that a body in periodic motion experiences in a unit of time.
After moving through a sequence of situations or locations and then returning to its initial position, a body in periodic motion is said to have experienced one cycle or one vibration.
Given that:
The red light emitted by a helium–neon laser has a wavelength of 632.8 nm.
We know that speed of light : c = 3×10^8 meter/second.
In wave motion:
speed = frequency × wavelength
⇒ frequency = speed/wavelength
= ( 3×10^8 meter/second)/( 632.8 nm)
= 4.74 × 10^14 Hartz.
Hence, the frequency of the light waves be 4.74 × 10^14 Hartz.
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A typical american family uses 1000 kwh of electricity pro 30 days. you may want to review ( pages 847 - 849) . part a what is the average rms current in the 190 v power line to the house?
=25.99 ohms
Explanation;A month has 30 days equivalent to 720 hours.
1000 kwh is equivalent to 1000000 watt,
Then 1000000 watt divided by 720
wattage per hour=1388.9
Therefore;
Wattage/hr divided by line voltage is equivalent av. current
= 1388.9 W/hr ÷ 190 v
= 7.31 amperes
Assuming that the load is 'resistive' and not inductive
Resistance is voltage divided by current;
= 190/7.31
=25.99 ohms
Which type of telescope focuses star light using mirrors?
Coudé telescopes use a convex secondary mirror like a Cassegrain and an angled mirror like a Newtonian reflector to move the light rays to a focal point away from the telescope. This arrangement is useful when optical equipment is being used that is too heavy to mount directly on the telescope.
Final answer:
Reflecting telescopes, also known as reflectors, focus starlight using mirrors. The main optical element in a reflecting telescope is a concave mirror, which reflects light and forms an image at the focus. Reflecting telescopes have different options for bringing the light to a focus, such as the Cassegrain focus.
Explanation:
Reflecting telescopes, also known as reflectors, focus starlight using mirrors.
The main optical element in a reflecting telescope is a concave mirror, which is curved like the inner surface of a sphere. This mirror reflects light and forms an image at the focus of the mirror. The mirror is coated with a shiny metal, such as silver, aluminum, or occasionally gold, to make it highly reflective.
Reflecting telescopes have different options for where the light is brought to a focus. For example, with a Cassegrain focus, light is reflected by a secondary mirror down through a hole in the primary mirror to an observing station below the telescope.
According to the graph above, how large of a force is needed in order to stretch the string 1.00 meters?
100 N
120 N
400 N
420 N
My guess for this one would be; 400 N
My reasoning would be; it starts at 0 on both X and Y, if you need to get to 1.00 meters thats 4/4. 1/4 of 1.00 is .25, and on .25 its on 100 so multiply it by 4 to make 1.00 and you get 400 N
Answer:
The needed force is 400 N.
Explanation:
We need to calculate the force for 1.00 m string
According to graph,
The force applied for stretch from 0.10 to 0.15 is 20 N.
0.10-0.15 = 0.05 m
So, the force applied is 20 N for 0.05 m.
For stretch 0.05 m = 20 N
For stretch 1 m = [tex]\dfrac{20}{0.05}= 400\ N[/tex]
Hence, The needed force is 400 N.
In the nucleus of an atom, two protons are separated are by a distance of 1*10^-15m. What is the magnitude of the electric force between them?
A. 115N
B. 720N
C. 142N
D. 230N
Answer:
D. 230 N
Explanation:
The magnitude of the electric force between the two protons is given by:
[tex]F=k\frac{q_1 q_2}{r^2}[/tex]
where
k is the Coulomb's constant
[tex]q_1 = q_2 = 1.6\cdot 10^{-19} C[/tex] is the charge of each proton
[tex]r=1\cdot 10^{-15} m[/tex] is the distance between the two protons
Substituting numbers into the formula, we find
[tex]F=(9\cdot 10^9 N m^2 C^{-2}) \frac{(1.6\cdot 10^{-19} C)^2}{(1\cdot 10^{-15} m^2)^2}=230.4 N \sim 230 N[/tex]
Whose famous conjecture is paraphrased as "space, time, and matter"?
The person who came up with this conjecture was Albert Einstein
Answer:
John Archibald Wheeler
Explanation:
the famous conjecture "space, time, and matter" is given by John Archibald Wheeler .
Albert Einstein stated that the fourth dimension is space time.
But John Archibald Wheeler was the physicist who later collaborator of Albert Einstein and work on the mission to achieve unified field theory.
John Archibald Wheeler stated that space time tells matter how to move and matter curves space time.
Force exerted by a person or object is called
Force exerted by a person or thing is called _____ force. applied. A change in the speed or direction of an object is called. acceleration. Force is a vector.
A charge of 100 elementary charges is equivalent to (1) 1.60 times 10^-21 C (2) 1.60 times 10^-17 C (3) 6.25 times 10^16 C (4) 6.25 times 10^20 C
Answer:
(2) 1.60 times 10^-17 C
Explanation:
The value of one elementary charge is
[tex]1 e = 1.60\cdot 10^{-19} C[/tex]
In this problem, we have 100 elementary charges: to find how many Coulombs it corresponds, we have to set up the following proportion
[tex]1 e: 1.60\cdot 10^{-19}C= 100 e : x[/tex]
And solving for x, we find
[tex]x=\frac{(1.6\cdot 10^{-19}C)(100 e)}{1 e}=1.6\cdot 10^{-17}C[/tex]
So, the correct answer is
(2) 1.60 times 10^-17 C
using the diagram at the right and thinking of what you have already leaned about the relationship between frequency and the wavelength of a sound wave, complete the two sentences here:
a. as a moving sound source approaches a stationary observer, the frequency of the sound increases, therefore the wavelength is_________(longer or shorter)
b. As the sound source moves away from the observer, the pitch of the sound __________ and the wavelength ___________.
a. as a moving sound source approaches a stationary observer, the frequency of the sound increases, therefore the wavelength is shorter
Explanation:
This effect is known as Doppler effect. When a moving sound source approaches a stationary observer, the wavefronts of the wave appear to be closer to each other: as a result, the frequency of the sound wave appears to be increased. The wavelength of the sound is inversely proportional to the frequency:
[tex]\lambda=\frac{v}{f}[/tex]
where v is the speed of the wave and f the frequency: therefore, as the frequency increases, the wavelength gets shorter.
b. As the sound source moves away from the observer, the pitch of the sound decreases and the wavelength increases
Explanation:
When the sound source moves away from the observer, the effect is opposite: the wavefronts appear to spread apart from each other, so the frequency of the sound appears to decreases, and as a result, the wavelength increases.
The pitch of a sound is related to how we perceive the sound, and it is directly proportional to the frequency: therefore, since the frequency decreases, the pitch decreases as well.
Before starting the simulation and having the waves encounter the barrier, the wavelength is manipulated. This is the (1. BLANK) variable.
The pattern of diffraction will vary as a result of the change in wavelength. The diffraction angle is therefore the (2. BLANK) variable.
A “constant” is a parameter that stays the same regardless of the variables. The parameter of the barrier that is held constant is the (3. BLANK).
1.) independent
2.) dependent
3.) gap width
Answer:
1. Independent
2. Dependent
3. width of barrier line
Explanation:
1. The independent variable is the one that does not depend on any variable and it can be set to any value. Thus, wavelength is Independent variable.
2. The dependent variable is the one which depends upon the value of other variables, like diffraction angle here depends upon the wavelength. Thus, diffraction angle is Dependent variable.
3. The parameter kept constant of the barrier is the width of barrier line. Multiple lines are drawn on diffraction grating to provide obstruction to wave. Their width is always kept constant.
Which type of electromagnetic wave travels through space the slowest?
All electromagnetic waves travel at the same speed, (as long as they're all in the same medium).
The speed at which they travel is what we call "the speed of light". But it's also the speed of infrared, the speed of microwave, the speed of radio, the speed of X-ray, etc.
The required, no electromagnetic wave travels slower than any other electromagnetic wave through space.
What is the refraction of electromagnetic waves?When an electromagnetic wave enters a medium other than a vacuum, such as air or water, its speed can be slowed due to the medium's properties.
In a vacuum, all electromagnetic waves travel at the speed of light, which is approximately 299,792,458 meters per second (or about 186,282 miles per second). As a result, no electromagnetic wave travels through space faster than any other electromagnetic wave.
However, this slowing of the wave is known as refraction. The amount of slowing depends on the wavelength of the wave, with longer wavelengths being more affected than shorter wavelengths by refraction. This means that in a medium other than a vacuum, electromagnetic waves with longer wavelengths, such as radio waves, may travel more slowly than electromagnetic waves with shorter wavelengths, such as visible light or X-rays.
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The sky looks blue during the day because the atmosphere scatters the light from the sun. The __________ rays are scattered more because they have shorter wavelengths.
Question options:
blue and violet
red, orange, and yellow
blue only
red only
Answer is blue and violet
The answer is blue and violet ask more answers if you need help with anything else and your welcome
Answer:
Blue and violet
Explanation:
This is the correct answer.
Methods of heat transfer worksheet
Define conduction:
Define convection:
Define radiation:
Conduction: conduction is the transfer of heat due to direct contact between two mediums, or between two parts of the same medium at different temperature. In conduction, the particles of the hotter medium vibrate faster than the particles of the colder medium, so the particles of the first medium transfer kinetic energy (by means of collisions) to the particles of the second medium, until when the two mediums reach the same temperature.
Convection: convection is the transfer of heat due to movement of masses of molecules in fluid. Convection occurs when a fluid is heated by an external source: the region of the fluid closer to the source gets warmer, so it expands and becomes less dense; as a consequence, it rises while the colder, denser regions of the fluid sink towards the source of heat. The process then continues forming the so-called "convective current", until the source of heat is turned off.
Radiation: radiation is the transfer of heat through electromagnetic radiation. Electromagnetic waves consist of oscillating electric and magnetic fields, which carry energy through space. Every object emits electromagnetic radiation, so every object transfer heat by radiation. This is the only method of heat transfer that does not require a medium to occur, since electromagnetic radiation can travel in vacuuum also.
Answer: Conduction: This is a flow of heat by direct contact. Heat travels from a warmer object toward a colder object.
Radiation: Radiation is the transfer of energy by electromagnetic radiation. Radiation does not require a medium in which the energy needs to transmit through. Solar radiation warming the Earth’s surface is an example. The radiation transfers from the sun through space and then strikes the Earth. All objects emit radiation. Colder objects emit longer wavelength radiation while warmer objects emit shorter wavelength radiation.
Convection: This is a transfer of heat by mixing a fluid. Convection occurs within liquids and gases. Examples include boiling water and when warm water mixes with cold water. In meteorology, convection is a common heat transfer mechanisms in the troposphere.
Explanation:
uring spring semester at MIT, residents of the parallel buildings of the East Campus dorms battle one another with large catapults that are made with surgical hose mounted on a window frame. A balloon filled with dyed water is placed in a pouch attached to the hose, which is then stretched through the width of the room. Assume that the stretching of the hose obeys Hooke's law with a spring constant of 130 N/m. If the hose is stretched by 5.50 m and then released, how much work does the force from the hose do on the balloon in the pouch by the time the hose reaches its relaxed length?
Answer:
1966 J
Explanation:
The work done by the hose on the balloon is equal to the elastic potential energy stored in it:
[tex]W=U=\frac{1}{2}kx^2[/tex]
where
k = 130 N/m is the spring constant
x = 5.50 m is the stretching of the hose before it is being released
If we substitute these numbers into the equation, we find:
[tex]W=U=\frac{1}{2}(130 N/m)(5.50 m)^2=1966 J[/tex]
So, the work done is 1966 J.
What happens to the particles of a substance as its temperature increases?
Answer :They move faster
They move faster and depending on the substance they evaporate or start to melt and release the liquid within.
Answer:
they move faster
Explanation:
smog is a homogeneous mixture heterogeneous mixture
Heterogenous mixture. Meaning it is a mixture of many different things in the air, other than just one thing (homogenous).
Smog is a heterogeneous mixture.
Explanation:
The mixtures are classified into two type depending upon their uniformity. When the mixture is uniformly distributed, it is called as a homogeneous mixture and when the mixture is spread in a uneven manner, it is called as an heterogeneous mixture. Smog is a chemical reaction which occurs when rays of light reacts with nitrogenous oxides. It is also a type of air pollution.
A cave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. The lift is performed in three stages, each requiring a vertical distance of 11.0 m: (a) the initially stationary spelunker is accelerated to a speed of 2.40 m/s; (b) he is then lifted at the constant speed of 2.40 m/s; (c) finally he is decelerated to zero speed. How much work is done on the 84.0 kg rescue by the force lifting him during each stage?
(a) 9305 J
Let's start by finding the acceleration of the spelunker, through the following equation:
[tex]v^2-u^2=2ad[/tex]
where
v = 2.40 m/s is the final velocity
u = 0 is the initial velocity
a is the acceleration
d = 11.0 m is the distance covered
Solving for a,
[tex]a=\frac{v^2-u^2}{2d}=\frac{(2.40 m/s)^2-0}{2(11.0 m)}=0.26 m/s^2[/tex]
Now we can find the force lifting the spelunker. The equation for Newton's second law applied to the spelunker is:
[tex]F-mg = ma[/tex]
where
F is the lifting force
m = 84.0 kg is the mass of the spelunker
g = 9.81 m/s^2 is the acceleration due to gravity
a = 0.26 m/s^2 is the acceleration
Solving for F,
[tex]F=m(a+g)=(84.0 kg)(0.26 m/s^2+9.81 m/s^2)=845.9 N[/tex]
And now we can finally find the work done on the spelunker by the lifting force F:
[tex]W=Fd=(845.9 N)(11.0 m)=9305 J[/tex]
(b) 9064 J
In this case, the speed is constant, so the acceleration is zero. So Newton's second Law becomes
[tex]F-mg=0[/tex]
From which we find
[tex]F=mg=(84.0 kg)(9.81 m/s^2)=824.0 N[/tex]
And so the work done is
[tex]W=Fd=(824.0 N)(11.0 m)=9064 J[/tex]
(c) 8824 J
The acceleration of the spelunker here is given by
[tex]v^2-u^2=2ad[/tex]
where
v = 0 is the final velocity
u = 2.40 m/s is the initial velocity
a is the acceleration
d = 11.0 m is the distance covered
Solving for a,
[tex]a=\frac{v^2-u^2}{2d}=\frac{0-(2.40 m/s)^2}{2(11.0 m)}=-0.26 m/s^2[/tex]
Newton's second law applied to the spelunker is:
[tex]F-mg = ma[/tex]
where
F is the lifting force
m = 84.0 kg is the mass of the spelunker
g = 9.81 m/s^2 is the acceleration due to gravity
a = -0.26 m/s^2 is the acceleration
Solving for F,
[tex]F=m(a+g)=(84.0 kg)(-0.26 m/s^2+9.81 m/s^2)=802.2 N[/tex]
And now we can finally find the work done on the spelunker by the lifting force F:
[tex]W=Fd=(802.2 N)(11.0 m)=8824 J[/tex]
Black holes are highly condensed remnants of stars. Some black holes, together with a normal star, form binary systems. In such systems the black hole and the normal star orbit about the center of mass of the system. One way black holes can be detected from Earth is by observing the frictional heating of the atmospheric gases from the normal star that fall into the black hole. These gases can reach temperatures greater than 1.10 106 K. Assuming that the falling gas can be modeled as a blackbody radiator, estimate λmax for use in an astronomical detection of a black hole. (Remark: This is in the X-ray region of the electromagnetic spectrum.)
[tex]\lambda_\text{max} = 2.63\times 10^{-9}\;\text{m}[/tex].
ExplanationThe peak emission wavelength of an object depends on its absolute temperature.
[tex]\lambda_\text{max} = \dfrac{2.90\times 10^{-3}}{T}[/tex],
where
[tex]\lambda_\text{max}[/tex] is the wavelength in meters where the emission is the strongest.[tex]T[/tex] is the temperature of the object in degrees Kelvins.For the gas falling into the black hole,
[tex]T = 1.10\times 10^{6}\;\text{K}[/tex].
Apply the formula:
[tex]\lambda_\text{max} = \dfrac{2.90\times 10^{-3}}{T} = \dfrac{2.90\times 10^{-3}}{1.10\times 10^{6}} = 2.64\times 10^{-9}\;\text{m} = 2.64 \;\text{nm}[/tex].
The question mentioned that [tex]\lambda_\text{max}[/tex] is in the X-ray region of the electromagnetic spectrum. According to Encyclopedia Britannica, the wavelength of X-rays range from [tex]10^{-8}\;\text{m}=10\;\text{nm}[/tex] to [tex]10^{-10}\;\text{m} = 0.1\;\text{nm}[/tex], which indeed includes [tex]2.64\times 10^{-9}\;\text{m} = 2.64 \;\text{nm}[/tex].
A 120 volt refrigerator uses 650 watts. Calculate how much work is done by the refrigerator in one hour.
A) 9.7 J
B) 39,000 J
C) 2,300,000 J
D) 4,100,000 J
1 Watt = 1 joule/second
650 watts = 650 joules/second
(650 J/sec) x (3,600 seconds/1 hour) = 2,340,000 Joules/hour
Answer:
C) 2,300,000 J
Explanation:
A 120 volt refrigerator uses 650 watts. Calculate how much work is done by the refrigerator in one hour.
A) 9.7 J
B) 39,000 J
C) 2,300,000 J
D) 4,100,000 J
power is the rate at which work is done by a machine.
work done is the product of force and distance,
it is also when energy is expended by a machine
energy can be dissipated by the refrigerator in form of heat
power=650W
time=3600 secs
work done will be 650*3600
2340000.
approximately 2300000J