Question

Figure shows three uniform spherical planets that are identical in size and mass. The periods of rotation T for the planets are given, and six lettered points are indicated—three points are on the equators of the planets and three points are on the north poles. Rank the points according to the value of the free-fall acceleration g at them, greatest first.

Answer 1

Fc=Fg

Answer 2

Well the gravity at b, d, and f would be less than it is at the equator right

Answer 3

Sorry would be stronger

Answer 4

Since they are ideal spheres, I think the gravity should be same everywhere on the surface ?

Answer 5

That's a good point

Answer 6

Yeah, I don't see why rotation would affect \[F=G\frac{mM}{R^2}\]

So based on that, the force should be the same at all 6 points... But maybe there's something I'm not including? Is this something to do with the Coriolis effect? I have no clue lol.

Answer 7

there is also centrifugal force on the surface if we switch to rotational frame

Answer 8

Yes! For that purpose I was thinking it maybe b, d, and f would have a stronger gravity but I barely remember first year physics haha...crap

Answer 9

what is coriolis effect ?

Answer 10

So the free fall acceleration at the equator is larger because as you fall you don't move but the earth below your feet does. So then that means I think:

e>c>a>b=d=f

Answer 11

I don't think coriolis effect has anything to do with it

Answer 12

does that mean you weigh more at poles and less at equator

if i get it wrong, it would be the opposite of above...

Answer 13

Well, it means the points at equator are moving faster than points at the pole

Answer 14

thats coriolis effect ?

Answer 15

Think so man, I barely remember this stuff

Answer 16

equator region moving faster than the pole region

Answer 17

makes sense... i have just seen a short video on why hurricanes rotate as we speak

Answer 18

This is sorta what I'm thinking, but I don't know what the Coriolis effect is so I dunno lol.