# Coriolis force direction

1. Oct 27, 2015

### nmsurobert

1. The problem statement, all variables and given/known data
4) Find the direction does the Coriolis force in the following case
a) a jet going north over the equator;
b) a rocket going up at the equator;
c) a pendulum at the equator viewed from above (please give the rotational direction.)
d) a rocket going up at the south pole. (zero)

2. Relevant equations

3. The attempt at a solution
ive been doing some reading on it and this is what i came up with. I read that the force follows a right hand rule so i hope im understanding it correctly.
a) the force is pointed east.
b) no force
c) no force
d)the force is pointed east.

for a) and d), i think i have them in the correct direction or in the opposite direction.
for b) and c) there is no force on the equator, right? so the force would be in no direction.

2. Oct 28, 2015

### haruspex

To get a rough idea, bear in mind that the effect of this perceived force is to deflect the motion as perceived by an observer moving with the Earth. E.g. for a rocket going straight up at a pole, why would the spin of the Earth make it look like it was doing something else?

That said, you have to be careful in some cases. There may be a deflection if watched over time, but at the precise location specified little or none. It's a bit like asking whether a stone dropped from rest is moving - well, no, it isn't immediately, but it very soon will be.
To be completely sure, apply the equations at https://en.wikipedia.org/wiki/Coriolis_effect#Rotating_sphere

3. Nov 4, 2015

### nmsurobert

i dont know why i didnt get the email notifying me that you replied....

all of us in class where really struggling with this so the teacher took the whole class period to cover coriolis effect. thanks for replying though!

4. Nov 4, 2015

### haruspex

Thanks for the update. For the record, I get
a) None
b) W
c) None
d) None
Would you mind posting the teacher's answers, if different?

5. Nov 4, 2015

### nmsurobert

sure.
1. none
2. west

she didnt go over the last two problems though. she had a new set of problems today that included the first two only. but if my understanding is correct then i agree with you on the last two being none.

6. Nov 4, 2015

Thanks!

7. Nov 4, 2015

### nmsurobert

no, thank you sir!