Register to reply

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

by Astaroth
Tags: earth, rotate, rotation
Share this thread:
cepheid
#55
Apr3-11, 10:28 AM
Emeritus
Sci Advisor
PF Gold
cepheid's Avatar
P: 5,196
Quote Quote by singh94 View Post
if the frictional force is constant ...... and the earth's speed be constant, how can we attain equilibrium?
Another doubt............ so we are moving with a speed of 1000miles per hourin west to est direction...... if i start runnning in the east to west direction at 5 miles per hour then what should be my real speed..... 995miles in the west to east direction or what?
There is no absolute notion of what is at rest and what is moving. All motion is relative. Speed is something that depends on the reference frame in which it is measured. In your example above, your velocity relative to the surface of the Earth is 5 mph, westward. Your velocity as measured in an inertial reference frame is 995 mph, eastward. Both statements are equally valid.

Quote Quote by singh94 View Post
ido i need to exert a force of 1005 miles per hour because if not then i am running in 2 opposite directions at the same time which is definitely not possible
This statement is nonsense. Force is not measured in miles per hour. Miles per hour is a unit for velocity or speed. I would highly recommend first reading up on some basic physics, and then later moving on to concepts like relative motion, before posting further on this issue.

EDIT: Beaten by a longshot!
JaredJames
#56
Apr3-11, 10:31 AM
P: 3,387
Quote Quote by singh94 View Post
a person who is in space out of earths atmosphere.
So? Is there a point to this statement?
singh94
#57
Apr3-11, 10:34 AM
P: 21
Quote Quote by jarednjames View Post
What first things to come into being?

Your father and mother are rotating with the earth, when you grow in your mother you are also rotating. The molecules you are made from have always been rotating with the earth.

It is only when you go back to the origins of earth that this argument is relevant. At which point, frictional forces come into play and are what set them in motion.

You are arguing that a human life being created is some mystical process and the molecules, particles, atoms etc "pop" into existence at that point and need to be accelerated. This is non-sense. You are made from materials already existing on the planet, moving with the planet.
see u r coming back to friction which is all we have been arguing about... so instead of talking about the origin of earth time why not explain the frictional force at this time as it will be more convinient.
im talking about anything hat came into existense dropped on earth from space from outer space anything which was not on earth initially. not about u and me being born so now instead of cutting my statements please answer them.
singh94
#58
Apr3-11, 10:38 AM
P: 21
Quote Quote by cepheid View Post
There is no absolute notion of what is at rest and what is moving. All motion is relative. Speed is something that depends on the reference frame in which it is measured. In your example above, your velocity relative to the surface of the Earth is 5 mph, westward. Your velocity as measured in an inertial reference frame is 995 mph, eastward. Both statements are equally valid.



This statement is nonsense. Force is not measured in miles per hour. Miles per hour is a unit for velocity or speed. I would highly recommend first reading up on some basic physics, and then later moving on to concepts like relative motion, before posting further on this issue.

EDIT: Beaten by a longshot!
i thought u people would be and mature enough to understand that im 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.
JaredJames
#59
Apr3-11, 10:38 AM
P: 3,387
Quote Quote by singh94 View Post
see u r coming back to friction which is all we have been arguing about... so instead of talking about the origin of earth time why not explain the frictional force at this time as it will be more convinient.
im talking about anything hat came into existense dropped on earth from space from outer space anything which was not on earth initially.
Read the thread, it's discussed it from the start.
not about u and me being born so now instead of cutting my statements please answer them.
Are you not, perhaps a quote of your earlier post:
Quote Quote by singh94 View Post
Yes...... but we come into existence when we are born so we have to be at rest first before we start moving with inertia.
Oh look, I'm not cutting anything up, I'm directly answering what you write.
Doc Al
#60
Apr3-11, 10:39 AM
Mentor
Doc Al's Avatar
P: 41,440
Quote Quote by singh94 View Post
im talking about anything hat came into existense dropped on earth from space from outer space anything which was not on earth initially. not about u and me being born so now instead of cutting my statements please answer them.
Have you already forgotten your earlier post?
Quote Quote by singh94 View Post
Yes...... but we come into existence when we are born so we have to be at rest first before we start moving with inertia.
singh94
#61
Apr3-11, 10:40 AM
P: 21
Quote Quote by jarednjames View Post
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
#62
Apr3-11, 10:40 AM
P: 3,387
Quote Quote by singh94 View Post
i thought u people would be and mature enough to understand that im 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
#63
Apr3-11, 10:42 AM
Mentor
Doc Al's Avatar
P: 41,440
Quote Quote by singh94 View Post
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
#64
Apr3-11, 10:44 AM
P: 21
Quote Quote by doc al View Post
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 earths gravitational field.
Now do u get wat i am trying to say?
Doc Al
#65
Apr3-11, 10:45 AM
Mentor
Doc Al's Avatar
P: 41,440
Quote Quote by singh94 View 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 earths gravitational field.
Now do u get wat i am trying to say?
No, not at all.
singh94
#66
Apr3-11, 10:47 AM
P: 21
Quote Quote by Doc Al View Post
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
#67
Apr3-11, 10:49 AM
P: 21
[QUOTE=Doc Al;3226931]No, not at all.[/QUOTE
then i give up trying to explain to u. maybe someone else will be able to.
singh94
#68
Apr3-11, 10:51 AM
P: 21
Quote Quote by singh94 View Post
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
#69
Apr3-11, 10:52 AM
Mentor
Doc Al's Avatar
P: 41,440
Quote Quote by singh94 View Post
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
#70
Apr3-11, 10:52 AM
Mentor
P: 15,155
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
#71
Apr3-11, 11:00 AM
P: 21
Quote Quote by Doc Al View Post
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 eachother 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 dont 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
#72
Apr3-11, 11:01 AM
P: 21
Quote Quote by D H View Post
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 :)


Register to reply

Related Discussions
Acceleration From Earth's Rotation Introductory Physics Homework 2
Calculating the Speed of the Earth's Rotation. Precalculus Mathematics Homework 5
Any Changes in Earth's Orbit or Rotation? Earth 21
Earth's rotation and gravitation Classical Physics 1
Earth's rotation and its mass Classical Physics 5