How can a plane fly if the earth spins faster?

Question

At the equator, the earth is spinning at 25,000 mph. A 747 cruises around 500-700 mph. How come when a plane is flying in the direction that the earth is spinning, it isn't actually going backwards? (and a side question that goes with this one; how come when you throw a tennis ball in the air in a plane, it doesn't smash through the back?)

Answer 1

The plane is actually already going about 25,000mph when its on the ground. In fact everything on this earth is already spinning as fast as the Earth is because we're on it. Just like when you're on a bus you're moving as fast as the bus is. When you jump you don't hit the back of the bus because you're momentum is keeping you at the same speed the bus is going.

When the plane takes off it will actually ADD to its already existing speed of 25,000mph and go to 25,500 - 25,700.

Answer 2

1

Answer 3

The plane flies at a speed relative to the earth --not a stationary point. At 25,000 mph (at most), the earth spins relative to a fixed point in space. When the plane sits at the terminal, it is moving along with the earth as it spins. Because our atmosphere moves with the earth, the plane continues to travel with the atmosphere as it flies. The 747 would be traveling 500-700 mph. This is either added to or subtracted from the spin of the earth, from a fixed point -- but never going backward -- even in the strongest headwind.
As for the tennis ball, it loses it forward momentum far too slowly to cause it to smash into the back of the plane. You should be able to toss it up and catch it just the same as if you were on the ground (for the most part).

Answer 4

The airplane starts out, like everything else on the earth, rotating along with the earth. So a plane on the equator is going that same 25,000 mph before it takes off. When it takes off it is still going at that same 25,000 mph plus whatever velocity its engines added. We can just talk about its speed RELATIVE to the earth and it is all simpler. When the plane is parked, it has a speed, relative to the earth of 0 mph (but it is going fast relative to the center of the earth, or the sun, or whatever).

Again, the plane and you and everything are going just as fast as the earth's surface (relative to the center of the earth) and you are still going that speed if you jump in the air.

The plane is flying in the air and the air is moving along with the earth also.

This is the same reason that when you jump, you don't land "up spin" from when you started.

Answer 5

We start at the same speed as the earth is rotating. If the plane is standing still on the earth, it is traveling at the rotation of the earth as is the atmosphere. The incremental speed of the jet engine adds or subtracts from the relative speed, someone was watching from the moon. This is the nature of relativity, by the way.

Consider if we were riding a train going 60 mph. That is our speed while sitting. If you stood up and walked forward in the train at 2 mph, you would look to an observer in a train station as if you passed at 62 mph. But to another passenger you look as if you were walking at 2 mph, not 60+2 mph. The jet flying relative to a ground observer is the same.

By the way, the earth at the equator IS 25,000 miles around and it takes one day to rotate. That means the earth is roughly traveling about 25,000miles/24 hours= 1000+miles/hr. not 25000 miles/hr

Answer 6

25000 mph? Where did you get that? If that were so, then one day would equal one hour. When a plane moves in the direction of the spin, it does take longer to reach the destination ie. if the plane is flying above the equator constantly. For international flights the planes usually go up North (Northern Hemisphere) and then come down. This makes the distance shorter.

Answer 7

Technically when a plane is going the opposite direction of the Earth's spin it is moving backwards. But it is moving in relation to the Earth's surface, so it looks like you are moving forward. Also, the atmosphere is moving with the Earth.

Answer 8

Even if there were a vacuum inside the plane the tennis ball already has the same speed as the plane because you, supposedly in a space suit, are holding it. When you throw it, it does not lose that initial speed, you are just adding to it.

This the principle of inertia which states that an object moving at a given velocity will continue to move at that velocity until a force speeds it up, slows it down, or changes its direction.

Answer 9

1) It's only 25000 mpd, not mph, and the air is moving right along with it at that same speed. So the plane already has ~ 1000 mph speed in an easterly direction before it takes off at the equator.

2) If a tennis ball would have that tendency, why not all the passengers, newspapers and napkins? The air in the cabin moves with the same speed THROUGH THE AMBIENT AIR as the outside of the plane.

Answer 10

The atmosphere, in which the plane is flying, is spinning with the earth.