Projection with coriolis force

[madking153]

hi,

i read lots of book regarding fictitious force - coriolis and centrifugal forces, but i am not clear how to determine the direction of the force..

example. if we throw a ball vertical up , how we can know the deviation from the original position ( from book we know that if the ball drop from a height - it will deviate to east )

pls explain or show the links regarding this two forces


thanks thansk

 

[Chi Meson]

THe Earth's surface is moving toward the east. If you threw a ball straight up, it would initially be moving eastward at the same speed as the Earth's surface. Ignoring any air resistance, the ball will continue to have this eastward speed.

As the ball gets higher, it would have to move eastward at a faster speed in order to stay above the same spot on the earth. This is just like the fact that the outside horse on a merry-go-round moves faster than the inside horse because it is at a larger radius.

Since the ball can not gain speed in the eastward direction, it "lags behind" the point on the Earth where it was launched. From the point of view of the Earth's susrface, it seems as if a force is pushing the ball westward, when actually it is the lack of an easterly force that causes the effect.

 

[quicknote]

for your question. The Coriolis force is a fictitious force that acts on objects in motion on a rotating frame of reference, such as the Earth. It is caused by the rotation of the Earth and is perpendicular to the direction of motion. This means that it will affect the direction of the object's motion, but not its speed.

To determine the direction of the Coriolis force, you need to consider the direction of the object's motion and the direction of the rotation of the Earth. In the example of throwing a ball vertically upwards, the Coriolis force will act to the right (east) in the Northern Hemisphere and to the left (west) in the Southern Hemisphere. This is because the Earth rotates counterclockwise when viewed from above the North Pole, so the Coriolis force will always be perpendicular to the direction of motion.

To better understand the Coriolis force, imagine standing on a rotating platform and throwing a ball towards a target. The ball will appear to curve to the right if you are facing the center of rotation, and to the left if you are facing away from the center. This is because the platform is rotating beneath the ball as it travels towards the target.

As for the centrifugal force, it is also a fictitious force that arises from the rotation of a frame of reference. It acts outwards from the center of rotation and is proportional to the mass of the object and the square of its velocity. In the case of the ball thrown vertically upwards, the centrifugal force will be negligible compared to the Coriolis force.

I hope this helps to clarify the concept of Coriolis and centrifugal forces. For further information, you can refer to sources such as textbooks on classical mechanics or online resources from reputable scientific organizations.