The force of Earth's gravity pulls down on a stone after someone tosses it off a cliff. What is the "equal and opposite force" d
1 answer:
The equal and opposite force is the force of the stone's gravity pulling up on thy Earth.
<u>Explanation</u>:
- When someone tosses a stone off a cliff, the force of gravity of Earth pulls down and the force of the stone's gravity pulls up on the Earth due to the equal and opposite reaction exerted between the Earth and the stone.
- In Newton's third law, two important features are present. One is the force exerted on two bodies will have the same magnitude but opposite direction. The other feature is force is acting on two different objects.
- This exerted force is equal in magnitude but opposite in direction whereas the gravity exerts a downward force on a stone and upward force on an Earth which is opposite in direction.
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1) Medium "b" has more optical density
2) Light must hit the interface between the two mediums perpendicularly
Explanation:
1)
Refraction occurs when light propagates from a medium into a second medium.
The optical density of a medium is given by its index of refraction, which is defined as:
where
c is the speed of light in a vacuum
v is the speed of light in a medium
Higher index of refraction means higher optical density, and light propagater slower into a medium with higher optical density.
In this problem, light propagates faster through medium "a" than medium "b": this means that medium "a" has lower refractive index of medium "b", and so "b" has more optical density.
2)
We can answer this part by referring to Snell's law, which gives the relationship between the direction of the incident ray and of the refracted ray when light passes through the interface between two media:
where
are the index of refraction of the two mediums
are the angle of incidence and of refraction (the angle that light makes with the normal to the surface in medium 1 and medium 2)
Here we want the direction of propagation of the light ray not to change: this means that it must be
(1)
However, here we have two mediums "a" and "b" with different index of refraction, so
Therefore the only angle that can satisfy eq.(1) is
So, the light must hit the surface perpendicular to the interface between the two mediums.
Learn more about refraction:
#LearnwithBrainly
Answer:
η = 1.31
Explanation:
The formula for the refractive index of from air to some other medium is given by the following formula:
where,
η = refractive index = ?
c = speed of light in air = 3 x 10⁸ m/s
v = speed of light in ice = 2.29 x 10⁸ m/s
Therefore, using these values in the equation we get:
<u>η = 1.31</u>
Answer:
Explanation:
The Spanish flu pandemic of 1918, the deadliest in history, infected an estimated 500 million people worldwide about one-third of the planet’s population and killed an estimated 20 million to 50 million victims, including some 675,000 Americans. The 1918 flu was first observed in Europe, the United States and parts of Asia before swiftly spreading around the world. At the time, there were no effective drugs or vaccines to treat this killer flu strain. Citizens were ordered to wear masks, schools, theaters and businesses were shuttered and bodies piled up in makeshift morgues.
Does this sound familiar?
Its the same thing but with a different name called the Corona virus pandemic the same thing happened in 1918 and now it is happening again in 2020 , but in in 2020 there are far less people infected by the Corona virus as compared to the Spanish flu the numbers approximate around 70 million infected and deaths are around 2 million.
The rapid spread of Spanish flu in the fall of 1918 was at least partially to blame on public health officials unwilling to impose quarantines during wartime. The public health response to the crisis in the United States was further hampered by a severe nursing shortage as thousands of nurses had been deployed to military camps and the front lines. But one of the chief reasons that the Spanish flu claimed so many lives in 1918 was that science simply didn’t have the tools to develop a vaccine for the virus. Microscopes couldn’t even see something as incredibly small as a virus until the 1930s.
That is why the Spanish Flu claimed so many lives in 1918 and the Corona Virus didn't claim that many.
The Corona Virus patients with respect to Spanish Flu patients exponentially decreased because in 2020 we had the specific tools to fight the virus and since mankind was aware when the world engrossed into the pandemic 100 years before the new the risks that it could impose on the world , People started to Quarantine themselves, more nurses/doctors are available rather than in the era of the 19th century.
Mathematically we would say that the exponential growth would be:
This is an exponential function, which means as you increase x , y increases exponentially, and where a is the initial value and b is the growth factor.
For example:
There are 100,000 cases of Coronavirus when the virus outbroke. If the number of cases doubles every week then how many cases would be there in 10 weeks?
So the solution would be
Which means people infected with the virus would be approximate 102.5 million. But since this kind of pandemic already broke out in 1918 called the Spanish flu mankind was wise and controlled its growth factor (b) by Quarantining people , shutting down businesses, schools and implying them to work from home , closing off cafeteria's restaurants for dine in purposes and just allowing take away to reduce human contact, and since 1918 we have more doctors and nurses to treat the infected in 2020 we reduced the outbreak to 70 million in about 10 months other wise it could have been 100 million in just 2.5 months as we can see.
So guys stay indoors just go out if you REALLY need something, avoid meeting others , wear masks and gloves :)