Speed of an aircraft in relation to the Earth's rotation

[aommaster]

There is something wrong with which I am going to say now, but I can't put my finger on it. Something must be wrong!

 

The Earth spins anticlickwise when looking from the North. Let's say a plane takes off from Britain and heads towards India or something. It is now travelling with the movement of the Earth, does that mean it is moving faster than the Earth's rotation?

 

Now, let's take the opposite. The plane is now heading towards the USA, it is going against the Earth's rotation. When it lands, shouldn't the plane, and its passengers be thrown backwards, because on the ground, it will be experiencing the movement of the Earth?

 

Something is all wrong here! Can someone please shine some light onto this subject?

[Skye]

The plane is flying through the atmosphere remember, and the atmosphere is dragged around with the earths rotation.

[blike]

An airplane is still subject to earth's rotation even in flight. For example, if you throw a ball up inside a moving car, the ball is stationary relative to your fixed point inside the car, even though the car is moving. If you throw a ball up, it doesn't suddenly shoot backwards because you're rotating away! (if so it would fly back at an apparent ~800 mph!)

 

Let's assume the earth is rotating around 800mph counter-clockwise at one point [if measured from space]. If an airplane takes off from this point and fly's AGAINST the earth's rotation at 400mph, the same observer in space will see the airplane actually flying with the earth's rotation, but 400mph slower, so the earth is rotating under the airplane.

 

Likewise if an airplane takes off and flies with the earth's rotation, an observer in space would calculate the airplanes speed to be the 800mph (earth's rotation) + 400mph(airspeed).

 

Bottom line: an airplane is still rotating with the earth just like a ball thrown inside the car is still moving with the car.

[aommaster]

Makes sene totally! So, what have I missed out? Is it the fact the plane is still subjective to the Earth's rotational speed?

[YT2095]

yes, because the plane is already traveling at 800mph(arbitrary figure) before it even leaves the floor

[aommaster]

hmmm.... so it is travelling faster than the Earth rotates? The final speed, the resultant one. How come that doesn't break the sound barrier?

[YT2095]

the plane and you while sitting on the ground are traveling at 800mph, I dunno about you, but it doesn`t feel like it

 

when the plane flies off at 400 mph towards the east it`ll be doing the same speed as to the west relative to its starting speed (that we may consider zero).

just like Blike said when tossing a ball in the air in a car at 60mph it`ll still just land in your lap, but to someone outside the car it`ll be doing 60mph, in fact if you open the window and let go of the ball just in front of them it would make a 60mph bruise on them and probably get you arrested!

 

but if you threw the ball backwards at 60 mph he would just see the ball land at his feet as if you were standing there and just dropped it in front of him

[aommaster]

oh, now i got it! Thanx alot!