Why do we rotate along with the earth's rotation?

[singh94]

So? Is there a point to this statement?

i mean what is my speed relative to a person who is in free space away from all forces and at compele rest.

 

[JaredJames]

i thought u people would be and mature enough to understand that I am just saying that do i need to exert a force which gives me a speed of 1005 miles so that i can run against the direction of the earth.

No, you don't.

If you are already at 1000mph, you only need to exert a force to give you an additional 5mph.

also i know what r the units of force velocity etc. which concern physics thank u very much.

Then show you do, stop posting statements which don't make sense and have incorrect units.

 

[Doc Al]

i mean what is my speed relative to a person who is in free space away from all forces and at compele rest.

Sorry, but the idea of something being at 'complete rest' is nonsensical. All motion is relative.

And being free from all forces would not define a velocity anyway. It just would mean that the velocity would remain constant (with respect to any inertial frame).

 

[singh94]

have you already forgotten your earlier post?

i am talking about anything that came on Earth when it was being created. Any thing from outer space (meteors aliens gases anything which was just moving in a straight line towards Earth due to its inertia or the Earth's gravitational field.
Now do u get wat i am trying to say?

 

[Doc Al]

i am talking about anything that came on Earth when it was being created. Any thing from outer space (meteors aliens gases anything which was just moving in a straight line towards Earth due to its inertia or the Earth's gravitational field.
Now do u get wat i am trying to say?

No, not at all.

 

[singh94]

Sorry, but the idea of something being at 'complete rest' is nonsensical. All motion is relative.

And being free from all forces would not define a velocity anyway. It just would mean that the velocity would remain constant (with respect to any inertial frame).

I am on Earth okay? i move in e-w at 5 miles per hour now wat is my speed for a person whos inertia of state is at rest and wh is not under an external forces?
also answer my other question concerning force for quiring speed of 1005 miles

 

[singh94]

No, not at all.[/QUOTE
then i give up trying to explain to u. maybe someone else will be able to.

 

[singh94]

I am on Earth okay? i move in e-w at 5 miles per hour now wat is my speed for a person whos inertia of state is at rest and wh is not under an external forces?
also answer my other question concerning force for quiring speed of 1005 miles

r u there Mr.Doc Al?

 

[Doc Al]

I am on Earth okay?

I'll accept that for the moment.

i move in e-w at 5 miles per hour now wat is my speed for a person whos inertia of state is at rest and wh is not under an external forces?

Again, a person who is 'at rest' is meaningless. Do you mean a person on Earth who is at rest with respect to earth? If so, then the relative speed is 5 mph, of course.

also answer my other question concerning force for quiring speed of 1005 miles

The force needed to change one's velocity depends on (1) how big a change you want and (2) how fast you want to change.

 

[D H]

Stop using text-speech, singh94. The correct wording is you rather than u, I rather than i, what rather than wat, are rather than r.

 

[singh94]

I'll accept that for the moment.

Again, a person who is 'at rest' is meaningless. Do you mean a person on Earth who is at rest with respect to earth? If so, then the relative speed is 5 mph, of course.

The force needed to change one's velocity depends on (1) how big a change you want and (2) how fast you want to change.

i mean a person who is in space. if everything was not moving(not at respect to each other but in actual) then he would be at rest with respect to them. now do u get it

finally i am on Earth and moving with the Earth constant speed of 1000 miles. if i move in opposite direction at a speed of x miles per hour and i reach the speed in 1 second then why don't i need a force of which can give me a speed of 1000+x miles in opposite diretion in 1 sec. otherwise i have two different velocities at same time 1000 miles in Earth direction an five miles in opposite direction which is not possible

 

[singh94]

Stop using text-speech, singh94. The correct wording is you rather than u, I rather than i, what rather than wat, are rather than r.

Gee i didn kno dat :)

 

[JaredJames]

finally i am on Earth and moving with the Earth constant speed of 1000 miles. if i move in opposite direction at a speed of x miles per hour and i reach the speed in 1 second then why don't i need a force of which can give me a speed of 1000+x miles in opposite diretion in 1 sec. otherwise i have two different velocities at same time 1000 miles in Earth direction an five miles in opposite direction which is not possible

No, you don't have two velocities.

You are either traveling at 1005mph east or 995mph east. Put simply, you are always traveling east unless you are going faster than 1000mph in a westerly direction.

 

[Doc Al]

i mean a person who is in space. if everything was not moving(not at respect to each other but in actual) then he would be at rest with respect to them. now do u get it

Just being 'in space' does not determine an object's velocity. It can have any allowable speed.

finally i am on Earth and moving with the Earth constant speed of 1000 miles.

OK.

if i move in opposite direction at a speed of x miles per hour and i reach the speed in 1 second then why don't i need a force of which can give me a speed of 1000+x miles in opposite diretion in 1 sec. otherwise i have two different velocities at same time 1000 miles in Earth direction an five miles in opposite direction which is not possible

Once again, a force is not associated with a velocity, but with a change in velocity. And that's only x mph.

As far as your velocity is concerned, that depends on what you are measuring it with respect to. With respect to the Earth's surface, it would be x mph. With respect to the Earth's center, it would be 1000 + x mph. With respect to the Sun, something else entirely. And so on.

 

[singh94]

No, you don't have two velocities.

You are either traveling at 1005mph east or 995mph east. Put simply, you are always traveling east unless you are going faster than 1000mph in a westerly direction.

yes u r right.

 

[JaredJames]

Gee i didn kno dat :)

I didn't know that

yes u r right.

you are

Really? Asking for trouble after being warned.

 

[singh94]

Just being 'in space' does not determine an object's velocity. It can have any allowable speed.

OK.

Once again, a force is not associated with a velocity, but with a change in velocity. And that's only x mph.

As far as your velocity is concerned, that depends on what you are measuring it with respect to. With respect to the Earth's surface, it would be x mph. With respect to the Earth's center, it would be 1000 + x mph. With respect to the Sun, something else entirely. And so on.

change in velocity is being 1000miles in east to 5 miles in west. also with Earth's center my v would be zero as the displacement is zero.

 

[singh94]

I didn't know that


you are

Really? Asking for trouble after being warned.

i don't kno wether it is u jarednjames or the original person but know that u can't force me to stop writing in short forms just cause u don't like it. either u bear with me, or u ignore me but stop trying to bully me OK?

 

[Doc Al]

change in velocity is being 1000miles in east to 5 miles in west.

Huh? Are you moving 5 mph with respect to the surface or 1005 mph? Kind of makes a difference.

also with Earth's center my v would be zero as the displacement is zero.

Huh? The surface of the Earth is moving with respect to the center at 1000 mph. (Roughly speaking, at the equator.)

 

[JaredJames]

i don't kno wether it is u jarednjames or the original person but know that u can't force me to stop writing in short forms just cause u don't like it. either u bear with me, or u ignore me but stop trying to bully me OK?

Forum rules say you can't, you agreed to them on signing up.

 

[Doc Al]

i don't kno wether it is u jarednjames or the original person but know that u can't force me to stop writing in short forms just cause u don't like it. either u bear with me, or u ignore me but stop trying to bully me OK?

Think twice about continuing to violate our rules.

 

[singh94]

Forum rules say you can't, you agreed to them on signing up.

allright then if that is the case ill stop imediately but i may make some slips here or there.

 

[singh94]

Think twice about continuing to violate our rules.

i APOLOGISE TO DOC AL JADERNJAMES AND ALL WHO TOLD ME TO STOP WRITING IN SHORT FORMS.
SORRY

 

[singh94]

Think twice about continuing to violate our rules.

the Earth is rotating the center may not move from its position but it is also rotating if u take the Earth and shrink it to the size of the center of the Earth then it would still rotate right? so the position of a point on Earth's surface to the center remains same.

 

[Doc Al]

the Earth is rotating the center may not move from its position but it is also rotating if u take the Earth and shrink it to the size of the center of the Earth then it would still rotate right? so the position of a point on Earth's surface to the center remains same.

No. Imagine a wheel spinning on its axle. The axle is fixed--its speed is zero (with respect to some frame). But the rim of the wheel is moving with respect to that frame. Same with the earth.

(Don't confuse rotational speed with translational speed.)

 

[jtbell]

u can't force me to stop writing in short forms

Hint: "Mentor" = "Moderator" here. Mentors have the power to ban people.

If you insist on using text-speak, you are welcome to find another physics forum that allows you to do so.

 

[JaredJames]

the Earth is rotating the center may not move from its position but it is also rotating if u take the Earth and shrink it to the size of the center of the Earth then it would still rotate right? so the position of a point on Earth's surface to the center remains same.

The further out you move away from the centre of the earth, the greater the distance you travel and the higher your velocity becomes.

A good example is a geostationary satellite. It is constantly above one point on the surface of the earth, but it's distance traveled and speed is many times greater.

 

[cepheid]

i thought u people would be and mature enough to understand that I am just saying that do i need to exert a force which gives me a speed of 1005 miles so that i can run against the direction of the earth.also i know what r the units of force velocity etc. which concern physics thank u very much.

I know that this has already been answered, but I felt that I should respond since it was addressed to me:

1. You mean that you thought that we would be psychic enough that we would somehow be able to make (correct) assumptions about your level of physics knowledge, in spite of the fact that you failed to communicate that level clearly? Well, NO, we can't read your mind. All we have to go on when it comes to gauging your physics knowledge are the things that you write. EDIT: and besides, there is no such thing as "a force that gives you a speed of 1005 mph." Any force CAN give you that speed provided you apply it for long enough time. Once again, based on what you have typed, we have no choice but to assume that you don't understand the impulse-momentum theorem.

2. You DON'T have to "run against the direction of the Earth." It's NOT like being on a treadmill, because you are MOVING WITH THE EARTH. In other words, if you don't move, it means you are stationary with respect to the Earth's surface. Even when you are standing still, it appears to an outside observer (who is not rotating with the Earth) that both the Earth and you (on it) are rotating at the same rate. Do you get it now?

Also, read the rest of the thread. You do NOT need to invoke friction at any point in history (not even going back to Earth's formation) to understand why everything that makes up part of the Earth is rotating. Only conservation of angular momentum need be applied.

 

[D H]

You do NOT need to invoke friction at any point in history (not even going back to Earth's formation) to understand why everything that makes up part of the Earth is rotating. Only conservation of angular momentum need be applied.

That's going a bit too far. In the long term, you cannot apply conservation of angular momentum for the simple reason that the Earth's angular momentum has not been constant. the Earth's rotation rate was considerably higher (4-6 times higher!) shortly after the Moon formed compared to its current rate. The atmosphere and oceans are not moving around the Earth at 4-6 times Earth rotation rate precisely because of friction.

 

[cepheid]

That's going a bit too far. In the long term, you cannot apply conservation of angular momentum for the simple reason that the Earth's angular momentum has not been constant. the Earth's rotation rate was considerably higher (4-6 times higher!) shortly after the Moon formed compared to its current rate. The atmosphere and oceans are not moving around the Earth at 4-6 times Earth rotation rate precisely because of friction.

Thanks. Yeah, that is a fair point. I failed to consider tidal effects.

Edit: but weren't the atmosphere and oceans being torqued on as well?