# Coriolis force question

by FermatPell
Tags: coriolis, force
 P: 22 1. The problem statement, all variables and given/known data Imagine that you are an observer in space (so you are in an inertial system), when the cannon (located on the equator) fires a cannonball in north direction. What does the trajectory of the cannonball look like from your perspective? Is it a straight line (that would mean that the cannonball is not affected by Earth's rotation) or something like a spiral? 2. Relevant equations 3. The attempt at a solution I think that, since the only real force acting on the body is the gravitational force, the trajectory is like a spiral. I also know that no Coriolis force exists in my inertial frame of reference. Am I right?
P: 1,395
 Quote by FermatPell I think that, since the only real force acting on the body is the gravitational force, the trajectory is like a spiral. I also know that no Coriolis force exists in my inertial frame of reference. Am I right?
The question is not so clear for me. This is what I think-
If you consider the earth to be an inertial frame of reference, then the trajectory of the ball would be a straight line.
If you consider the earth to be a non-inertial frame of reference (take its rotation in account), then the trajectory of the ball would be similar to a spiral.

In both the above cases, you are in an inertial frame of reference, so there will not be any Coriolis force.
 P: 1,284 If you don't shoot the cannonball faster than escape velocity, the orbit will be an ellipse. Look up two-body problem. Of course the ellipse will intersect the surface of the earth again at some point.

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