Rotation relative to an inertial frame

[johnny_bohnny]

Earth has a huge angular velocity regarding its rotation. Now let's imagine that the Earth has the velocity of 400 km/s relative to some inertial frame. What will be the velocity of Earth when we take the rotation into account combined with inertial motion? How do the 2 combine?

Thanks in advance.

 

[Dale]

Earth has a huge angular velocity regarding its rotation.

I think that you mean "huge tangential velocity". The angular velocity is not huge, it is 0.00007 1/s. The tangential velocity is about 0.5 km/s at the equator, which may or may not be "huge" depending on the context.

What will be the velocity of Earth when we take the rotation into account combined with inertial motion? How do the 2 combine?

Velocities add vectorially. Don't forget that the tangential velocity is pointing in a different direction at each point on the earth, so you can do this addition for each point on the Earth and you will get a different value.