Even a spinning coin loses its speed of rotation & stops after sometime.How does earth spin,non-stop for ages?

Question

A coin spins due to the force of the hand that spinned it and due to the friction in the ground but finally stops spinning at a point of time. A ball spins in mid air due the force of the hand that threw it but finally stops and falls to the ground. Please explain the law of motion that makes the earth rotate on its own axis in a vacumn for millions of years. There is no friction of the ground, there is no force that threw it. But it does have a certain gravitational pull from the sun and all other planets around it. My doubt is how can gravitational pull of other planets and the sun make it spin round and round on its axis for ages? Also please explain the law of motion, with suitable easy examples so that even a kid can understand. What makes the planets rotate on its axis and revolve on its individual revolutionary path? Explain revolution and rotation in a much simpler way with examples? Thank you so much

Answer 1

The earth is in space which is a vaccum. That means there is no friction. We are inchin a few feet closer to the sun every year, but it'll be millions of years (at least) before that's a problem.

Answer 2

I'm just going to clarify that the sun's gravitation doesn't cause the Earth to spin on its axis, but it is why the Earth revolves around the sun. The Earth has actually been spinning for BILLIONS of years, since it cooled from hot gases when our solar system first developed. The reason why it keeps spinning is because there are no forces acting on it in a manner that would slow it down (for the most part), but interestingly enough, the Earth is slowing down a bit. As for the Earth and the other planets revolving around the sun, I'll give you a simple explanation of a complicated theory. Einstein stated that space and time are interwoven into a fabric-like "continuum" which you can think of a blanket being stretched out. If you put something heavy in the middle, it sinks down because of the objects weight. This sagging of the "fabric" is caused by gravity, and the planets are just following a path around the sunken center, like water spinning around the outside wall of the toilet as you flush. A crude, but somewhat effective example. Check out www.howstuffworks.com for more about gravitation and other questions you might have. Its a cool website.

Answer 3

The question is a trick. The earth IS slowing, at a measurable rate, just like the coin. The planets rotate because the primordial "ooze", as it were, that they were formed of was spun off from the core of our solar system billions of years ago. These speeds have slowed over the course of said billions of years due to entropy (through heat loss), so the question cannot simply be answered via law of motion, without adding laws of entropy, conservation of motion and physical formulae into a wide mix. Hence the reason physics is such a wide ranging science.

Basically, the mass of the planet (planets, since our solar system is a self-checking system due to gravity), gravity, and the initial spinning force all come together to explain the continuing rotation. If the coin had been spun at a high enough rate of speed, in a vacuum, with almost zero drag-force, then it too would still be spinning.

Answer 4

Both examples that you used, you said it yourself, there is a force, but that force is not continuous, thus the coin or ball must stop at some time, due to some friction, and lack of force, the rotation will slow down, and stop. Now I am not sure how Earth started to rotate, but since the gravitational pull of the sun is constant, and the initial velocity of the earth is also constant, because both Earth and the sun are HUGE masses, Earth will continue to rotate around the sun. Its called centrifical (spelling) force. This is the CONSTANT force on Earth. NOW- if you were to constantly spin the coin, it would never stop. try it, you might beable to get the coin to spin for a couple minutes just by constantly flicking it. Also, when you see ball players spinning a ball on their finger, some can keep spinning it with extra FORCE. Just look at the Harlem Globetrotters, or some of the street ball players. They can make the balls spin for minutes. This is because of constant force onto the ball by their hands. Now just relate this to the constant force of gravitational pull by the sun, and the velocity of Earth, and viola, there is your answer. HOPE THIS HELPS!

Answer 5

When we rotate the coin it spins and stops after few seconds because earth's atmosphere contains many many minute particles like air and etc so the coin stops due to friction with the air particle and also ground where as solar system does not contains atmosphere or any minute particles that will cause friction to earth and also the gravitational force of the sun make the earth to revolve around it

Answer 6

as far as friction goes it works against motion of a body
gravitational force is due to mass i.e every body that has mass will hv gravitational force , more the mass ,more the force.
coin or ball stops coz of friction
earth is moving coz of the gravitatinal force of the sun,yeah right.but why does earth does not get pulled towards the sun
bcoz even earth pulls the sun with some force,and when both of them cannot further pull each other earth starts rotating & revolving as force is still being exerted
as far as spinning trhu ages goes-- as earth and sun have mass for ages,so also they have exerted force for ages

Answer 7

earth was formed out of small and large rock that were pulled by the larger ones (gravitation). The impacts created angular spin. since there is no friction, its motion continued till today. Moons orbit along with other natural phenomenon increased the angular spin rate. however, earth is slowing down gradually. big dams throughout the world are also responsible for this!! there is something called conservation of angular momentum, that says when small spinning object's radius is increased, the velocity decreases. tall buildings, volcanoes etc are increasing earth's radius, thus earth is decreasing its spin rate.

well your kid must be know it by now,,8 years have passed

Answer 8

it is slowing down, by like a squillionth of a second per year. The answers above help explain why it seemingly will go on forever, mass, vacuums etc.

The Asian Tsunami that hit on Boxing day 2004 caused a jolt so large that the earth actually spun FASTER by a fraction of a second and we "lost" time. (Think of an ice-skater doing a fast twirl-they get faster when they tuck their bodies in-in the same way, the earth got "pinched" at the equator and spun faster for a fraction of a second)

But the sun only has 1billion years of power left and that will finish things off before the earth slows down.

Answer 9

i am not very sure.. but thought that the reason why earth was continuing its rotation is to follow the law of conservation of angular momentum. the earth is rotating and revolving in space where there is not much friction.
it is believed that planets are formed by the breaking of a larger mass and an angular momentum was imparted to them at that time. unless an external force/ a net external force acts on it. since no net external force is acting on earth the angular momentum remains the same and the earth continue to rotate at the same speed.
to explain conservation of angular momentum, one can take the example of a dancer, who is rotating on his own axis. to increase the speed, he will bring his arms closer, while to reduce the speed he will extend it. angular momentum is measured as moment of inertia * angular velocity.
Hope this helps yo in some way! :)

Answer 10

nice question and soem good answers. i will stick to the huge inertial factos. but no one mentioned the fact that deeper regions of the earth are made of gases and liquid masses that also rotate. earth expiriences drag due to friction by the way.ther is an atmospere responsible for this. the fact that it continues to move in cercular orbits around the sun promotes its revolution along its axis