The frequency observed by Francis when the train approaches is 297.4 Hz.
Doppler effect
The frequency observed by Francis is determined by applying the principle of Doppler effect.
The frequency observed by Francis is calculated as follows;
[tex]f = f_o(\frac{V}{V \pm V_s} )[/tex]
where;
f is the source frequencyf₀ is the observed frequencyVs velocity of the source when it is moving towards the observerV is velocity of sound45 km/h = 12.5 m/s
Speed of sound in air = 343 m/s
Since the train is moving towards the observer, the frequency heard by the observer will be greater than the source frequency, thus we will choose positive sign for the source velocity.
[tex]f = f_o(\frac{V}{V + V_s} )\\\\287 = f_0 (\frac{343}{343+ 12.5)} )\\\\287 = 0.965f_0\\\\f_0 = \frac{287}{0.965} \\\\f_0 = 297.4 \ Hz[/tex]
Thus, the frequency observed by Francis when the train approaches is 297.4 Hz.
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The rate of change of momentum of a body free falling under gravity is equal to its? A. Velocity B. kinetic energy C. power D. weight
Answer:
weight
Explanation:
this is because of the lighter the object the faster it will be affected
.
A bowling ball has a mass of 3 kg & is moving at a speed of 10 m/s.
What is its kinetic energy?
Answer:
150 j
Explanation:
K.E. = 1/2 m v ^2
= 1/2 * 3 * 10^2 = 150 j
A toy train is going around a circular track of a radius of 1.2 m as shown on the diagram. The train takes 9 seconds to complete one lap of the circular track.
(a) Calculate the speed of the train
(B) on the diagram draw in the train's velocity and acceleration vectors at B. Label clearly.
(c) For the train to move in a circle like this there
must be a centripetal force acting on it.
Explain how this force is being produced
Explanation:
r=1.2, Period(T) = 9s
a) Speed(V) = ωr
ω = 2 x Pi(3.142) x frequency
frequency = 1/period
therefore; the frequency will be 1/9 = 0.1Hz
Therefore Speed(V) = 2 x 3.142 x 0.1 x 1.2=0.75m/s
C) Centripetal and centrifugal forces are the forces experienced by rotating objects. The centripetal force keeps an object moving in a circle and is always pointed toward the center of that circle. For instance, the gravitational force of the sun is a centripetal force that keeps the Earth orbiting around it. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path.
A 30kg bullet strikes a tree trunk of diameter 40cm at 200ms and leaves it from the opposite side at 100ms find the kinetic energy of the bullet just before it strikes the tree
Answer:
Before it strikes the tree:
KE = 1/2 m v^2 = 1/2 * 30 kg * (200 m/s)^2
This KE would be 6.0E5 Joules
30 kg would about 66 lbs - obviously too heavy
You might consider 30 mg = .03 kg (still quite heavy)
KE = 1/2 * .03 kg * 40000 m.s^2 = 600 J more realistic
When an old information system in shut down and a new system starts up right after the shut down, we call this a __________ inforomation system conversion. phased parallel plunge pilot
Parallel information system is when an old information system in shut down and a new system starts up right after the shut down.
What is an information system?An information system is a system in which information are passed or transmitted from one end to another especially from senders to receivers to achieve a particular goal.
Therefore, Parallel information system is when an old information system in shut down and a new system starts up right after the shut down.
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When you transfer energy to a drum through a drumstick or your handhow does the amount of energy affect the sound the drum makes? Explain using the Crosscutting Concept of Energy and Matter
Answer:
Striking the head of the drum changes its shape and compresses the air inside the shell. The compressed air presses on the bottom head and changes its shape. Then, these changes are transmitted to the drum shell and reflected back, and this action is repeated, creating a vibration. These vibrations of the top and bottom heads create vibrations in the air, which become sound, and eventually, as the head vibrations are dampened, the sound diminishes.
Explanation:
define one kilogram mass
Answer:
The amount of a certain global prototype was created of platinum-iridium and held at the International Bureau of Weights and Measures.Explanation:
Hopes this helps.radiation from which type of decay has the least energy
Answer:
Alpha decay is the least penetrating. This is because the Alpha particle produced during the decay process is relatively large and low in energy thus it is easily 'blocked' and does not travel far through space.
Explanation:
The Earth pulls on the Sun with the same magnitude force that the Sun pulls on the Earth. If these forces are equal, why does Earth go in orbit around the Sun? Why does Earth experience a great centripetal acceleration, while the Sun doesn't?
Answer:
For every force there is an equal and opposite reaction force.
For instance, if one wants to find the acceleration of a person standing on a scales, he uses the force exerted by the scales on the person,
One doesn't consider the reaction force of the person on the scales.
Likewise for the force of the sun on the earth
m v^2 / R = G M m / R^2 descibes the force acting on the earth to produce the centripetal acceleration of v^2 / R
The sun experiences the same centripetal acceleration as the earth, but since the mass of the sun is about 333,000 times the mass of the earth the acceleration can be ignored for most purposes.
When a satellite experiences an acceleration of v^2 / r, the earth is undergoing the same centripetal acceleration. However since the mass of the earth is much greater than that of a satellite and the centripetal acceleration of the earth is ignored.
State Newton's law of motion.
Answer:
In the first law, an object will not change its motion unless a force acts on it. In the second law, the force on an object is equal to its mass times its acceleration. In the third law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction.
Explanation:
As the projectile goes upward, what energy changes take place?.
Answer:
Initial kinetic energy is transformed into potential energy.
An object initially at rest on a horizontal surface is set into motion by the application of a force. Does the force of friction between the object and the surface decrease, increase, or remain the same immediately after the object starts to move?
Answer:
C always
Explanation:
The force of friction between the object and the surface decrease immediately after the object starts to move.
What is friction?The force preventing solid surfaces, fluid layers, and material components from sliding past one another is known as friction.
The definition of static friction is: The resistance people feel when they attempt to move a stationary object across a surface without actually causing any relative motion between their body and the surface they are moving the object across.
The resistance that is formed between any two items when they are sliding against one another is known as sliding friction.
It is experimentally proved that the force of friction between the object and the surface decrease, immediately after the object starts to move.
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Distinguish between infrasonic and ultrasonic sound waves.
How we could distinguish them is that the infrasonic sounds are the lower limit of human hearing while ultrasonic sound is above human hearing. The sound of frequency more than 20,000Hz are called ultrasonics while the frequency less than 20Hz are called infrasonics.
Explanation:
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What are some downsides to fossil fuels? (Select all that apply.)
They release large amounts of carbon dioxide when burned.
They are in a limited supply.
They are expensive to extract compared to other forms of energy.
They do not replenish themselves.
Answer:
They release large amounts of carbon dioxide when burned.
They are expensive to extract compared to other forms of energy.
They do not replenish themselves
Explanation:
What is the SI (metric) unit of FORCE?
A. meter
B. newton
What is the SI (metric) unit of FORCE?
B. newtonwith symbol ( N )
All the best !
Answer:
B, Newton,
Explanation:
B. Newton defined as the Force which when applied to 1 Kg mass produces an acceleration of 1 m/s/s.
F = m * a.
A primary difference between momentum and kinetic energy is momenta can cancel; kinetic energy cannot. kinetic energy can cancel; momenta cannot. either of the above depending on circumstances none of the above
The primary difference between momentum and kinetic energy is kinetic energy can cancel momentum.
What is kinetic energy?The kinetic energy of an object is the energy possessed by the object due to its motion.
KE = ¹/₂mv²
where;
m is mass of the objectv is the velocityWhat is momentum of object?Momentum of an object is the measure of the rate at which a mass is moving.
P = mv
K.E = ¹/₂(P)v
Thus, the primary difference between momentum and kinetic energy is kinetic energy can cancel momentum.
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Which of the following can explains convection?
A.Hot air is less dense than cold air.
B.The wind blow takes place from higher position to lower position
C.The particles in hot air are lighter than those in cold air.
D.The gas pressure of hot air is greater than that of cold air.
E.The particles in hot air move quicker than that of cold air.
Answer:
A) would be the best explanation because hot air is less dense and would rise to the top of a column of air
Which equation expresses the conservation of mechanical energy in a system where the only forms of mechanical energy are kinetic energy and elastic potential energy?
a.
1/2mvi2 + mghi = 1/2mvf2 + mghf
b.
1/2mvi2 + mghi + 1/2kxi2 = 1/2mvf2 + mghf + 1/2kxf2
c.
1/2mvi2 + 1/2kxi2 = 1/2mvf2 + 1/2kxf2
d.
mei = mef
c it hink this because im geuss
please answerrrr need this asapppp
Answer:
A
Explanation:
It depends on the scale of the volcanic eruption. A smaller eruption may only affect the nearby area, but a large one can affect the whole world. For example, the Krakatoa eruption of 1883 created an ash cloud which lowered global temperatures and affected the climate for a year afterwards.
An explosive eruption by a single volcano can affect only the lifeforms living on the volcano. The correct option is B.
What is a volcano?A volcano is an opening in the Earth's surface through which molten rock, ash, and gas can escape. Volcanoes are formed by the movement of tectonic plates, which create weak spots or vents in the Earth's crust where magma can rise to the surface.
Volcanoes can form in different ways, but most are formed at plate boundaries, where one tectonic plate is moving under another (subduction zone), or where two plates are moving away from each other (divergent boundary). When magma rises to the surface, it can form a volcanic cone or mountain over time.
There are three main types of volcanoes, based on their shape and the type of eruptions they produce:
(i)Shield volcanoes - broad, gentle slopes formed by lava flows that spread out over a wide area.
(ii)Stratovolcanoes (also called composite volcanoes) - tall, steep-sided cones formed by alternating layers of lava, ash, and other volcanic debris.
(iii)Calderas - large, basin-shaped depressions that form when a volcano collapses or erupts so forcefully that it empties its magma chamber.
Volcanoes can be active, dormant, or extinct. Active volcanoes are those that have erupted recently or are expected to erupt soon, while dormant volcanoes have not erupted in a long time but could still erupt in the future. Extinct volcanoes are those that have not erupted in thousands of years and are unlikely to erupt again.
Here in the question,
An explosive eruption by a single volcano can have a significant impact on the surrounding environment and local communities, but its effects are generally limited to the immediate vicinity of the volcano. The eruption may release ash, gases, and lava flows that can cause damage to nearby ecosystems and affect the health of humans and animals living in the area. However, the effects are unlikely to extend beyond the local region, let alone affect lifeforms throughout the world.
Therefore, B. only the lifeforms living on the volcano, is the correct option.
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In a gamma decay process __________.
A. a high-energy electron is released
B. a product is a positron
C. a parent nuclide was in an excited state
D. a high-energy alpha particle is produced
Explanation:
D.
hope it's help
hi I'm new user
Answer:
D.
Explanation:
The answer should be D. Cause it makes more sense and the gamma decay process it goes from Unstable to stable.
I apologize if it is incorrect-
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An astronaut lands on another planet and wishes to determine the acceleration due to gravity.the astronaut measure a period of 0.5m pendulum as being 3.2 seconds what is the acceleration due to gravity
Answer:
1.927 m/s^2
Explanation:
period = 2 pi sqrt ( l/g)
3.2 = 2 pi sqrt (.5/g) =1.927 m/s^2
PLEAASEEEE HELPP ASSPPP SHORT RESPONSE WILL GIVE BRAINLY
Australia's skin cancer rate is so high. The Australian Health Alliance has asked you to write a short argument that explains this to the Australian public. Remember to
explain how your evidence supports your claim to make your argument as complete and convincing as possible. You can agree with one or both of the claims.
Question: Why is Australia's skin cancer rate so high?
Claim 2: There is something different about the sunlight in Australia.
Claim 3: More people in Australia have skin that is easily damaged by sunlight.
Answer:
Claim 2
Explanation:
Australia's skin cancer rate is so high because of the climate and the weather in their area. It is also because since australia is on the bottom of the globe, the continent recieves higher UV radiation.
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1.Australia has one of the highest rates of skin cancer in the world. This is due largely to our climate, the fact that many of us have fair skin that isn't really suited to such harsh conditions, our proximity to the equator (high UV levels) and our social attitudes and love for the outdoors.
2.Australia's unusually harsh sunshine results mainly from its location in the Southern Hemisphere. The elliptical orbit of the Earth places the Southern Hemisphere closer to the sun during its summer months than the Northern Hemisphere during its summer.
3.Basically, through migration, our two countries have been populated by many people with fair skin whose ancestors come from much less sunny climates. Lack of protective pigmentation leaves skin cells especially vulnerable to the DNA-damaging rays from the sun.20 Mar 2018
Which terrestrial world has the most atmospheric gas?.
Answer:
Venus
Explanation:
It has the most atmospheric gas, and it’s made up of 96% of Carbon Dioxide and around 3.5% of molecular nitrogen.
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Which is an example of current electricity
When observed from earth, the wavelengths of light emitted by a star are shifted toward the red end of the electromagnetic spectrum. This redshift occurs because the star is:.
Answer:
When observed from Earth, the wavelengths of light emitted by a star are shifted toward the red end of the electromagnetic spectrum because: the star is moving away from planet Earth.
A star is a giant astronomical or celestial object that contains a luminous sphere of plasma and bounded together by its own gravitational force.
A redshift can be defined as a displacement (shift) of the spectral lines of celestial or astronomical objects toward longer wavelengths (the red end of an electromagnetic spectrum), as a result of the Doppler effect.
Hence, a redshift is considered to be a subtle change in the color of visible electromagnetic radiation from stars (starlight), as observed from planet Earth.
In conclusion, a redshift occur when observing a star from planet Earth because the star is moving away from planet Earth.
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Explanation:
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In the photoelectric effect, electrons are ejected by matter only if they are given energy from light of a high enough frequency. It does not matter how bright the light source is; only frequency matters. Which reasoning explains why particles are better than waves for describing this phenomenon?(1 point)
The energy from the waves of light coming from bright lights would add up and free an electron.
The energy from light waves is canceled out by interference at low energies, but not at high energies, so it can free electrons with bright light.
The energy from photons of light would never be enough to free electrons because they don't have the same energy if they are just particles.
The energy from photons of light should be enough to knock out an electron, no matter what the frequency of light is, because it is moving so fast.
Answer:Answer is A:The energy from the waves of light coming from bright lights would add up and free an electron.
Explanation:
1. They collect evidence and make sure that the model can be used with reasoning to explain the evidence.
2. The energy from the waves of light coming from bright lights would add up and free an electron.
3. The spots are the result of interference, which happens with waves but not particles.
4. This is not something that waves do because they need a medium to travel through, while particles do not.
5. When the electromagnetic wave peaks overlap, a bright fringe forms.
I promise this is correct because i failed and this is what it said if this is ever wrong they must have changed the quick check
An object is being acted on by a force of 20 N directed to the left and a force of 30 N directed to the right. What is the net force acting on the object
Answer:
10 newtons to the right
Explanation:
the net force is the sum of all forces.
so let's say the force acting on the left of the object is negative and the force acting to the right is positive.
so:
30 - 20 = 10 newtons.
since the force is positive we can say that the net force is 10 newtons to the right
A diesel engine has an efficiency rating of 50%. One gallon of diesel contains 146,520,000 Joules of energy. A dodge 1 ton truck gets 24km per gallon, fuel economy. With that information, calculate how much Force it requires for a dodge 1 ton truck to drive 2 km.
PLEASE HELP!
What is the angular speed, in rad/s, of a flywheel turning at 813. 0 rpm?.
Answer:
The angular speed will be 85.13 rad/sec
Explanation:
Our earth is situated in the milky way galaxy. The milky way galaxy is which type of galaxy?.
Answer:
Our earth is situated in the Milky Way galaxy. The Milky Way galaxy is a type of spiral galaxy.
Explanation:
spiral galaxy
The Milky Way is a huge collection of stars, dust and gas. It's called a spiral galaxy because if you could view it from the top or bottom, it would look like a spinning pinwheel. The Sun is located on one of the spiral arms, about 25,000 light-years away from the center of the galaxy.