Why is it if the Earth is in constant motion a ball placed on the ground or floor Will stay stationary?
405941
as I think u need to know about the relative velocity. If the Earth is in constant motion so all the stuff on the Earth are all in constant motion with speed equal to that of the earth.  \nkey point is that the ball move with the earth.\nWhile the ball placed on a table will not move unless u apply a force to it.(The 1st law of motion) When u move the table forward the table will move forward but the ball would remain in its place if there would not be any friction present between the ball and table.
227905
When you lift a ball off the floor, you transfer energy to it. This energy is stored in the gravitational force between the ball and the earth and is called gravitational potential energy. When you release the ball, its weight makes it accelerate downward and its gravitational potential energy gradually becomes kinetic energy, the energy of motion. When the ball hits the floor, both the ball's bottom surface and the floor's upper surface begin to distort and the ball's kinetic energy becomes elastic potential energy in these two distorted surfaces. The ball accelerates upward during this process and eventually comes to a complete stop. When it does, most of the energy that was initially gravitational potential energy and later kinetic energy has become elastic potential energy in the surfaces. However, some of the original energy has been converted into thermal energy by internal frictional forces in the ball and floor. The distorted ball and floor then push apart and the ball rebounds into the air. Some or most of the elastic potential energy becomes kinetic energy in the ball, and the rising ball then converts this kinetic energy into gravitational potential energy. But the ball doesn't reach its original height because some of its original gravitational potential energy has been converted into thermal energy during the bounce.
104921
because the earth are moving around the sun so thats y..its never disappear.
465388
The Earth is round for the same reason that things don't fall off it.  Gravity is a force in the universe that attracts all forms of matter equally, this means that pieces of matter will eventually move together and form clumps, if this is happening from every direction then the most likely shape it will form is a sphere.\n\nThis gravitational attraction is pretty small.  However, the Earth is pretty big, so the combined effect of all that gravity is just enough to keep your feet firmly planted on the surface :)\n\nThere are a few other related effects that come into play, such as centrifugal force, which keeps everything spinning and moving.
66594
everyone else is pretty much right, it's just that everything in the universe is relative to an object's frame of reference. nothing is absolute. for example, you're on a bike moving at 10 m/s. you throw a baseball at 15 m/s relative to your frame of reference. to someone standing nearby, from their frame of reference the ball is moving at 25 m/s (the 15m/s you threw it at plus the velocity you're already moving.)  now, to a car moving slowly along the road at 25 m/s, the ball is not moving at all. it is stationary in the frame of reference of the car because they are moving at the same speed as each other. this is why it doesnt feel like you're moving backwards when you're in a car at a constant velocity(only when you speed up or slow down). also, if you drop a book in a moving vehicle, it will go straight down, not down and to the back.  that is because everything in the car is moving at the same speed, they're all in the same frame of reference. if you were to drop a  ball outside of the window of the car(assuming no air resistance) the ball would be moving at the same speed as the car and continue bouncing alongside the car(in reality it slows down substancially due to air resistance.) to you the ball would be stationary, aside from bouncing up and down, but to an outside observer, it would be moving forward.  it's all relative... that's the basic concept but there's also a lot more, more advanced applications involving the distortion of time as you reach near-light speed velocities... pretty interesting stuff.
675679
you'd fall very quickly and then go past the centre towards the surface at the other side.\nThen you'd start to fall back to the centre and go back to the other side.\nThis is basically how a pendulum works.\nBy the way.. there should be free fall at the centre of the earth... I.e. no gravity.
792649
If it were on a frictionless surface, the ball (or any object) would remain stationary relative to the ground and slide backward relative to the wagon, until it fell off the wagon (assuming there's nothing preventing that). But since the object is a ball, I'm guessing the question involves the ball rolling, which will happen if there is friction. In that case the ball won't remain stationary since it is being accelerated in rotation, and the tangential force needed to do that, applied through frictional contact, also accelerates the ball forward. The ball will move forward relative to the ground, but backward relative to the wagon.\nSo not enough information has been supplied for a definite answer.
591806
No, this is not perpetual motion, and the ball would not make it up the other side to come out again.\n\nThis is due to the fact that there is air resistance which would slow the ball down, even if it is very aerodynamic.  It would hit terminal velocity rather quickly, and not be able to accelerate any further.  So, in its trip back "up" the other side, it will not have nearly enough velocity to make it all the way up.\n\nThe friction with the air would eventually cause the ball to come to a stop, at a point roughly midway between the ends of the pipe (at the center of gravity).
950717
in order for perpetual motion to occur, both surfaces have to be frictionless, and there can't be any air density.  Eventually, the ball in your question will stop as a result of friction from the table and air resistance.
844498
You have uncovered one of the secrets of the universe. Simple Harmonic Motion (SHM) surrounds us in every aspect of the universe. It is the lowest common denominator. Even Newton got it slightly wrong in his First Law where he said that a body will continue in uniform motion until an external force acts upon it. There is nowhere in the known universe that gravity does not exist.\n\nConsider an air table which is flat and which extends in all directions by a million miles, and it rests on the earth. place a puck on it and give it a gentle nudge. It will move off in the direction you push it at an apparently constant velocity, however it will eventually stop and return to the point where it started because of the earth's gravitational field. It will shoot past and head off in the opposite direction until it stops again, being pulled back by the earth's gravitational field. It will continue this way forever (ignoring all friction), oscillating in simple harmonic motion. \n\nNewton's problem was that he was restricted to observing a very small portion of the SHM path, so it seemed linear.\n\nAnyway, congratulations, you are on the path to unlocking the secrets of the universe.
895329
When you hold a ball up in the air, it develops potential energy because gravity wants to pull it down.  As the ball is dropping, that potential energy became kinetic energy, but loses some energy because of friction with the air.  At impact more energy is lost to the ground via thermodynamics (heat loss) and deflection (strain energy transfer).  The ball bounces back up with the remaining energy.  Something like that, better to ask a physics professor in high school or college :)
1094922
The Earth is continually rotating on its axis.\n\nIn short, the Earth rotates because it has to in order to help conserve angular momentum in the universe.\n\nThere is a physical Law which states that angular momentum must always be conserved.\n\nThe big ball of gas and debris which out solar system was formed from had some value for its angular momentum (even if that value was zero).  When the sun and the planets formed from that material, in order to conserve the angular momentum, the planets and sun started rotating.  If you add up all the angular momentum there is now between all the planets/the sun, moons/.... it should come out to be the same value as the angular momentum of the material which formed out solar system.
940178
remains constant   coz u have inertia of motion
481150
the earth spins at 1500 mph.  If you take a ball and spin it extreemly fast you will find that the center of the ball will grow and the poles will flatten.  It is like driving a car very fast.  The higher up ion speed you go the lower to the ground it will become.  I has to do with Volocity.
506705
Provides inertia in order to stabilize a trajectory.  If an object is still, it tends to stay still.  If moving, it tends to keep moving.  Helps to compensate for the effects of gravity.
12398
The rotational energy you impart to the object when spinning overcomes the force of gravity that would topple a stationary object.  \n\nA total layman's explanation:\n\nA perfect stationary top perfectly balanced will not fall over.  In real life though,it's impossible to perfectly balance a top.  It's shape practically guarantees that its center of gravity will not be directly over the balance point for any practical length of time.  Imperfections in the material will cause a slightly uneven weight distribution, air currents will introduce a small force, and mechanical vibrations will be transmitted through the medium the top rests on.  The upshot of all this is that as soon as the center of mass is no longer over the resting point, gravity is going to pull the top over.  \n\nNow gravity has an acceleration of 32 feet per second squared (if I remember my ancient high school course correctly).  It can only topple the top at a specific speed.  If you spin the top fast enough, any side that gravity tries to "pull down" will translate around so quickly that it literally has no time to fall.  If you were standing on a planet with a much higher gravity, you'd have to spin the top far faster to achieve stability, and if you were on the moon, it would spin for a much longer time. Eventually, however, the top starts to slow and the tip will inscribe little circles.  That action is called "precession".  And of course, eventually the thing drops to the table and the game is all up once it slows enough.\n\nAgain, that's a layman's view of how it works.  Some college physics major is probably going to come in here and make my answer look really foolish.
64466
Yes! There is centripetal acceleration on the ball.  It is actually accelerating in towards the center, but other forces keep it on the edge.