It is a well known fact that the Earth is spinning. Centrifugal force acts upon all occupants of a spinning object of any kind, in this case, the Earth. This force acts by pushing the objects atop the surface (people, buildings, animals, et cetra) away from the epicenter of rotation, the Earth's crust, counteracting the force of gravity by a certain ammount. If the Earth were to come to a complete stop, centrifugal force will no longer take effect, therefore revealing the true, unaltered force of the the Earth's gravity. What would be the force of gravity if the Earth were to stand still?
137542
Add v2/R.\nv=speed of rotation at the suface of the earth.\n(it depends on the geographic altitude fi)\nR = radius of the earth.
372148
The earth is round and its gravitational pull draws us to its center.  Upside-down is really just pointing away from the core...from anywhere.
435629
I think you meant to say that the people were running forward, not in place.  If they were running in place, nothing changes.\n\nOtherwise, assuming that an average person has a mass of 70kg.  That means that all the people have a combined mass of about 70*6.4*10^9 = 448*10^9 kg.  The earths mass is approximately 6*10^24 kg.  That means that all of the peoples mass is only 0.00000000000007466667 of the earths mass.  Using the conservation of angular momentum with:\nm = moment of inertia of people\nM= moment of inertia of earth\nw_1 = angular velocity of earth with people standing still\nw_p = angular velocity of FORWARD running people\nw_e = angular velocity of earth while people are running \n\nw_1*(m+M) = w_e*M + w_p*m\n\nso by the conservation of angular momentum you can see that you would effect the rotation of earth.  However m compared to M is essentially zero, as mentioned before (mass is in a way related to ineria) so setting m = 0, you get:\n\nw_1*(m+M) = w_e*M + w_p*m\nw_1M = w_e*M\nw_1 = w_e\n\nThe effect that this would have is practically none so no you will not change the direction but, yes you do slow the earth down a tiny, tiny, minuscule amount.
453050
Your friend is half right.  What keeps the earth in orbit is the gravitational pull of the sun.  Why doesn't the earth crash into the sun?  Because the inertia of the earth (or any other object in an orbit) is always at a right angle to the centripital force.  \n\nCentripital force is literally the center seeking force.  It is always directed to the of the orbit.  The velocity or direction of motion is always at a 90degree angle to this force.  Since the direction of motion and acceleration are always changing, the object can be constantly accelerating and constantly in motion without ever getting any closer to the center.
137787
You would have to overcome the spinning motion of the atmosphere.  See my answer to your "if the world stopped spinning" question.  So yes, if you could reach about 900 mph going west, you would be counteracting the spinning of the Earth and eventually be somewhere else "without moving".  Now about the Earth's orbit around the sun...
59602
gravity is highest at the centre of the earth. so you will be accelerating towards the centre.since there is no resistence (assume so that there is no air), you would not stop at the centre due to inertia of motion and continue to go beyond the centre to teh other side. but due to increasing pull on you, you will turn back and continue to oscillate about the center of the earth.\n\nits good for theory but humanly imposible
331104
Gravity is a force of attraction here on earth that always pulls us toward the center of the planet.  Mass has a gravitational field.\n\nWhat I think that exterterrestrial life may have is some way of generating "anti" gravity such that the gravity here on earth would then repel an object.  It would be like having a "negative" mass.\n\nI think advanced propulsion systems would utilize such a drive, and who knows, some of these things that have been seen might just be the work of our government in secret.
511828
It's an inertial force which arises in this case from the conservation of angular momentum.  When the disc is rolling, it has angular momentum with a certain magnitude, and a particular direction - it is turning around a horizontal axis.  For it to come to rest, the angular momentum has to be transferred by friction to the earth, and if you change the axis, that is equivalent to adding some angular momentum around a different axis, so that added momentum has to be dissipated too.  The forces against your feet were caused by the disc trying to transfer some its angular momentum to you, probably not very effectively.
147209
Yes the earth would move but not that anyone would notice.\n\nEvery time you push off from the earth, the earth moves \nat a velocity equity to -your_velocity* your_mass/earth_mass.\n\n6 billion people would be less than 600  tons while the earth is about 5,972,000,000,000,000,000,000 tons
665705
theoretically it is, as we consider the earth to be a round sphere. it is not  a sphere though, thus gravity is less at the equator, or Himalaya, and more at the poles. one can calculate the difference if they want, if we know the exact distance from the center of the earth to the point where we are. going further we would have to take into account the lack or excess of mass due to the landscape (mountains, and/or lakes, canyons) at the area. going further, we would have to take into account the position of other planets, as their mass interferes. a bit further we have to take into account the speed of the rotation of the earth, as it is not constant, and a bit further, the angle of the rotation. a bit further, we have to add the mass that is being added as material from space falls on earth. the list can go on and on, one thing is certain: gravity exists, (well, maybe not inside my head,) but it is not exactly the same everywhere, and it is not exactly the same all the time
338242
Gravity, centrifugal forces and centripetal forces
57573
The Earth was formed spinning (like a top) and it just hasn't stopped spinning since then.  There is very little friction that would slow it down (space is pretty empty).\n\nThere are different theories as to why it was created spinning.  But most likely it formed from gas and dust that was swirling, and that angular momentum is still with us today.
76842
2 masses dropped from a given height are subject to air resitance (assumed: only phy resistance)...thus earth's pull on either is same & ofcourse insignificant. On the contrary two masses rolled from the top of a slope are subject to the earth's terrain & friction. Also it is believed that the earth's gravitational pull could slightly vary  from point A to B. These "could" cause a variance in their acc.\n\nI believe we're looking at objects of the same mass here.
130138
The Coriolis effect. If the Earth were not rotating, the effect would be a mysterious "fifth force" with no physical explanation. See the source for details. \nAccelerating frames are absolutely determined. The above references to relativity theory are completely incorrect; Newtonian theory equates frames with constant velocity, Einstein equates an accelerating frame with a local curvature (gravitation). This is all the two theories have to do with the badly referenced quotations above.\nThe amount of pseudoscience and bad science on these forums is strange, given the amount of knowledge freely available over the internet.
116604
The law you are referring to is the law of inertia, which is directly related to the laws of gravity.  The heat from the sun and it's gravitational pull are what "make the earth go round"
272144
From what i understand the earth will eventually leave the earth system altogether in a few hundred thousand years, this process is not however do to tidal drag. That force is responsible for slowing the rotation of the earth (and other planets) What most people don't understand is that the moon acts as a stabilizer for the earth. they degree of axial tilt would vary wildly. the equator may wind up as the north pole and go back again. planets without moons all experience this extreme wobble effect.
407832
To understand this quandary you must look at a much bigger picture. since gravitational force is determined by an objects mass the earth actually exerts a much greater force on the object than the object exerts on the earth. Now this is where you must remember Newton's second law - if an unbalanced force acts on an object the object will accelerate in the direction of the force. The unbalanced force is the force of gravity the larger mass (earth in this case) exerts on the smaller object. The acceleration in the direction of the force is what we call gravity. It is true that the object exerts a reaction force but the maximum force it exerts is only the force of gravity it can generate based on it's mass. Since it weighs less it's force is not strong enough to move the earth.