Quiz - Question of the Day

[chanduchamaar]

Re: Quiz - Question of the Day

@TLK

Nice one kkf:k:

The area near the surface of the earth can be divided up into four inter-connected “geo-spheres:”

Name at least two.

never heard the term “geosphere”. are they lithosphere, hydrosphere, atmosphere, biosphere?

[Eastern_Dresses]

Re: Quiz - Question of the Day

@chanduchamaar

well this is an awesome thread !

i would like to add.
we do not know YET whether Gravitational force is unified with the other fundamental forces of nature or not. The other fundamental forces were not unified by US, they were already unified, we(Maxwell for electro-magnetic force) just discovered it and are now able to write equations proving them being connected. You’ve given an excellent point(their levels of operation) as to why it has been difficult for us to find out the link between Gravitation and the others.

technically, gravity == acceleration due to gravity

True, I’d agree that Gravitation Force is not unified with the other forces YET. No one said other forces were unified by us. I mentioned they are are believed to be one force at the beginning and later were isolated as different forces (as the earth cooled and started to shape into mass and wasn’t not just a ball of energy).

I am not so sure what you are trying to say about gravity though

[chanduchamaar]

Re: Quiz - Question of the Day

@Eastern_Dresses

True, I’d agree that Gravitation Force is not unified with the other forces YET. No one said other forces were unified by us. I mentioned they are are believed to be one force at the beginning and later were isolated as different forces (as the earth cooled and started to shape into mass and wasn’t not just a ball of energy).

I am not so sure what you are trying to say about gravity though

i wasn’t correcting you, i just added some more(unrequired) info. to the discussion. i wouldn’t dare correct you. you seem to know very well whatever you speak(write). Like when you say that all of the fundamental forces were believed to be a single force at the beginning, and later they were isolated when the temperature of the universe fell. It is consistent with what scientists believe that at extremely high temperatures, all fundamental forces are unified into a single force.

About gravity,
in textbooks they refer to gravity as the acceleration due to gravity. i’ll explain.
suppose there are 2 bodies of masses m1 and m2. the gravitational force of attraction between them would be equal to : F= Gm1m2/r[SUP]2[/SUP]
where ‘r’ is the distance between the two bodies and ‘G’ is the universal gravitational constant.
according to Newton’s 2nd law of motion: force=massacceleration or F=ma
so if for any one of the bodies (say m1) the (gravitational) force acting on it would be F= m1*(Gm1/r[SUP]2[/SUP]), where m1 is its mass and Gm1/r[SUP]2[/SUP] is its acceleration. lets say Gm1/r[SUP]2[/SUP] = g, so for the body with mass m1, F = m1g
so the ‘g’ here is the acceleration m1 experiences due to the gravitational force exerted by m2

this ‘g’ is different for different bodies. on earth is it 9.8m/s[SUP]2 /SUP, on the moon it is about 1.6 m/s[SUP]2[/SUP].
technically when we say gravity, we refer to this ‘g’

I KNOW all the above wasn’t required but i had the time and i wanted to rekindle some of my elementary physics. Sorry for the long post. Thanks for reading.

[chanduchamaar]

Re: Quiz - Question of the Day

^ the tilt in the earth's axis causes seasons...since earth revolves around sun in an elliptical path so the northern hemisphere is away from sun in winter so it's cold [winter] while the southern hemisphere is closer to the sun so it's warm in there...[summer]

there's an awesome concept of Continentality here. tum logo ko pata hai kya?

[aaliyahkhan1]

Re: Quiz - Question of the Day

Much more interesting than all the kiddy questions I asked before :o

[TLK]

@chanduchamaar:9701780

[quote="“TLK, post:6, topic:286386"”]

Nice one kkf:k:

The area near the surface of the earth can be divided up into four inter-connected “geo-spheres:”

Name at least two.

never heard the term “geosphere”. are they lithosphere, hydrosphere, atmosphere, biosphere?
[/quote]

Yes you’re right. :k:

[TLK]

@chanduchamaar:9701987

[quote="“Eastern_Dresses, post:2, topic:286900"”]

True, I’d agree that Gravitation Force is not unified with the other forces YET. No one said other forces were unified by us. I mentioned they are are believed to be one force at the beginning and later were isolated as different forces (as the earth cooled and started to shape into mass and wasn’t not just a ball of energy).

I am not so sure what you are trying to say about gravity though

i wasn’t correcting you, i just added some more(unrequired) info. to the discussion. i wouldn’t dare correct you. you seem to know very well whatever you speak(write). Like when you say that all of the fundamental forces were believed to be a single force at the beginning, and later they were isolated when the temperature of the universe fell. It is consistent with what scientists believe that at extremely high temperatures, all fundamental forces are unified into a single force.

About gravity,
in textbooks they refer to gravity as the acceleration due to gravity. i’ll explain.
suppose there are 2 bodies of masses m1 and m2. the gravitational force of attraction between them would be equal to : F= Gm1m2/r[SUP]2[/SUP]
where ‘r’ is the distance between the two bodies and ‘G’ is the universal gravitational constant.
according to Newton’s 2nd law of motion: force=massacceleration or F=ma
so if for any one of the bodies (say m1) the (gravitational) force acting on it would be F= m1*(Gm1/r[SUP]2[/SUP]), where m1 is its mass and Gm1/r[SUP]2[/SUP] is its acceleration. lets say Gm1/r[SUP]2[/SUP] = g, so for the body with mass m1, F = m1g
so the ‘g’ here is the acceleration m1 experiences due to the gravitational force exerted by m2

this ‘g’ is different for different bodies. on earth is it 9.8m/s[SUP]2 /SUP, on the moon it is about 1.6 m/s[SUP]2[/SUP].
technically when we say gravity, we refer to this ‘g’

I KNOW all the above wasn’t required but i had the time and i wanted to rekindle some of my elementary physics. Sorry for the long post. Thanks for reading.
[/quote]

I think you are confusing yourself with gravitational force vs acceleration due to gravity. Even their units are different. Gravitational force (G) unit is N(m/kg)^2 and acceleration due to gravity (g) is m/s^2. One is force and other is acceleration.

Also, Newton 's law of Gravitation is fundamentally wrong. It’s very static in nature as its written. F= Gm1m2/r^2 will immediately change if you remove or change one of the masses. In reality, it’s not true. If m1 is the mass of earth, and m2 is the mass of Sun in this equation, and if somehow Sun vanishes from our solar system this very moment, then according to the Newton 's law of Gravitation, earth will feel the change of force that very instance. In reality, it will take earth full eight minutes before it would feel any difference.

[TLK]

One of the very famous rule that scientists use while forming theories is,

"The simplest explanation is usually the right one"

This rule is known as

1. Heisenberg's principle
2. Occam's razor
3. Schrodinger's paradox
4. Murphy's law
5. Planck's constant

[aaliyahkhan1]

Re: Quiz - Question of the Day

Murphy's Law?

[Blacklisted_Prince]

Re: Quiz - Question of the Day

Occam's Razor :)

[Southie]

Re: Quiz - Question of the Day

It is 1 or 2 by elimination. I will go with the blacklisted one (since have been in the doghouse of late!)

[chanduchamaar]

Re: Quiz - Question of the Day

@TLK

I think you are confusing yourself with gravitational force vs acceleration due to gravity. Even their units are different. Gravitational force (G) unit is N(m/kg)^2 and acceleration due to gravity (g) is m/s^2. One is force and other is acceleration.

Also, Newton 's law of Gravitation is fundamentally wrong. It’s very static in nature as its written. F= Gm1m2/r^2 will immediately change if you remove or change one of the masses. In reality, it’s not true. If m1 is the mass of earth, and m2 is the mass of Sun in this equation, and if somehow Sun vanishes from our solar system this very moment, then according to the Newton 's law of Gravitation, earth will feel the change of force that very instance. In reality, it will take earth full eight minutes before it would feel any difference.

i never confused myself. i HAVE written the ‘g’ in units of m/s[SUP]2.[/SUP] and the units of force as per my equations come out to be Nm[SUP]2[/SUP]/Kg[SUP]2.
[/SUP]
**what i intended to say was : when someone says ‘gravity’, technically he/she is saying ‘acceleration due to gravity’ and is not saying ‘gravitational force’. **

i’m sad i couldn’t express it well.

the equations are more accurate when they’re expressed in differential form. so F=ma should be, F = md(v)/d(t) + vd(m)/d(t) am i correct?

[chanduchamaar]

Re: Quiz - Question of the Day

the only name i haven't heard, Occam's Razor. pretty sure the other don't translate to anything like that. school to theek hai, college mein bhi nahi padhaya Occam's Razor :(. btw under which discipline is it taught?

[Southie]

Re: Quiz - Question of the Day

Competition to Gillette et al. Buffett may be interested.

[Southie]

Re: Quiz - Question of the Day

@chanduchamaar

i never confused myself. i HAVE written the ‘g’ in units of m/s[SUP]2.[/SUP] and the units of force as per my equations come out to be Nm[SUP]2[/SUP]/Kg[SUP]2.
[/SUP]
**what i intended to say was : when someone says ‘gravity’, technically he/she is saying ‘acceleration due to gravity’ and is not saying ‘gravitational force’. **

i’m sad i couldn’t express it well.

the equations are more accurate when they’re expressed in differential form. so F=ma should be, F = md(v)/d(t) + vd(m)/d(t) am i correct?

a=dv/dt
So f is just mdv/dt

[chanduchamaar]

Re: Quiz - Question of the Day

@Southie

a=dv/dt So f is just mdv/dt

that is only an incomplete equation, because F = d(mv)/d(t). and writing it as F = m*d(v)/d(t) won't explain what TheLastKryptonian is pointing out.

[TLK]

You guys are right. Is Occam's razor.

[TLK]

True or false (bold part)

We know that summit of Mt Everest is the highest point above sea level. That means that it is the furthest point from the center of the earth.

[Southie]

Re: Quiz - Question of the Day

Abscolutely, positively, beyond a reasonable doubt, TRUE

[Southie]

Re: Quiz - Question of the Day

that is only an incomplete equation, because F = d(mv)/d(t). and writing it as F = m*d(v)/d(t) won't explain what TheLastKryptonian is pointing out.

Didn't realize force was rate of change of momentum.