Why do upper-level winds in the middle latitudes of both hemispheres generally blow from the west?

Question

Please help me with this question. It's for a homework assignment

Answer 1

Imagine yourself as the earth,spin to your right,as you do this you notice that the air around you,you'll feel it move from right to your left side.so this is why we have it as it is,because the earth spins on its axis in a right to left scenario,or east to west.
But why does it exist,eg; below,of why.
Now consider that your the size of the earth with an equator,and your spinning in the same direction,but because your waist is like the earth equator it gets Heat at a constant thermal ray from the sun,that heat has to go some were,so it migrates to your upper body(northwards to the poles on the earth).
But wait a minute as the air moves further north the air going towards the poles loses momentum because of the changes in the circumference of the planet,however because the earth is moving in an east west direction the wind tends to lag behind as it moves further north, so it playing catch up as it is no longer over the equator,but as it dose this it also makes it way towards the poles so as to allow heat to escape there equalizing our temps so it not too hot or cold, and all this is because the earth has an atmosphere,which is held in place by the right conditions and gravity.
And this is what we see in the form of the Jet stream which moves from west to east that also carries along with it cold fronts and other weather phenomenons,n for millions of years over the middle latitudes.