Speed of Earth and how we remain on Earth.

[amt7565]

Question:
The Earth is travelling at a speed of about 15miles/sec (aproximately). Let's consider an example: we throw a baseball high up in the air and the ball falls back after 5 seconds. But by this time the Earth would have travelled 75 miles (15 x 5 = 75) and the ball would have landed in a place 75 miles from where we would have initially thrown the ball from. But apparently that does not happen.

What am I missing?
Thanks for everyone's input.

Regards-
AMT.

[orbsycli]

this is just like when you throw a ball out of a moving car.
your velocity is added to how fast you are moving.
car 50mph
ball 40mph
ball now traveling 90mph

earths spin DOES affect the balls movement when you throw it up, but it's very very small.

when a space shuttle takes off, it's actually going straight up but since earth is spinning it's smoke path looks curved.

[orbsycli]

sorry i can't be more ellaborate, i'm more of a listener.

[amt7565]

Thanks.
But I was referring to the linear velocity of the Earth it self, not the angular velocity of its spin. The Earth itself is travelling through space at a speed of about 15 miles/sec right?

In the case of the car, it's assumed that we are throwing the ball in the direction of the car's directional velocity. So this way we can add both the velocities together.

Now let's take the example of the car again: In case we throw the ball upwards when the car is travelling, then the ball is surely going to fall behing us...OR would it not?
I was applying the same rule to the Earth instead of the car.

What am I missing?
AMT-

[orbsycli]

if there was no air resistance, the ball would just go up, come down, and land back in your hand.
but since there's air resistance, the ball would be pushed behind.

[C1ay]

Originally Posted by amt7565

The Earth itself is travelling through space at a speed of about 15 miles/sec right?

And the Earth's atmosphere is travelling through space with it, right?

[Aki]

I'm not sure if my explanation is correct:

If the Earth is travelling at 15 miles/hour, then we are also traveling at 15 miles/hour in space, right?
So basically, 15miles/hour is the horizontal velocity. When we throw the ball up in the air, we are giving it some vertical velocity. The total velocity of the ball is the vector sum of the vertical and horizontal velocity, which is 15 miles/hour. The horizontal velocity is remains the same because it is not affected by gravity. Therefore the balls travels horizontally just as much as we travel in space, so it makes it seems like the ball is moving straight up and straight down.

[amt7565]

The Earth travels at a fascinating 15 miles/second.

Let's analyze this example: We are travelling in a BMW convertible at 100 MPH. Someone in the back seat throws the ball straight up. I agree that since we are throwing the ball while in motion, we would have both horizontal and vertical component vectors. Now let's ignore the air resistance etc. Do you think after about 5 seconds, the ball would still fall insider the speeding BMW?

What if we were travelling in a plane at 1000MPH and did the same thing? I am sure there should be a speed threshold at which we will NOT be able to catch the ball, right?

AMT-

[orbsycli]

why would there be?

[Qfwfq]

Originally Posted by Aki

I'm not sure if my explanation is correct:

Your explanation is quite correct Aki!!!

It is really the principle of relativity. One can find a discussion of it in Galileo's dialogue, arguing against those who thought the Earth must be still simply because we don't feel that it's moving.