# Since the earth is spinning, wouldn't centrifugal force make us lighter?

• ben328i
In summary: This centrifugal force causes the body to move away from the center of the Earth at a faster rate than if the body were at the center.
ben328i
so here is my questions
since the Earth is spinning, wouldn't centrifugal force make us lighter?
if we were not spinning would we be heaver?
how come i do not have gravity?
what is gravity

ben328i said:
so here is my questions
since the Earth is spinning, wouldn't centrifugal force make us lighter?
if we were not spinning would we be heaver?
Yes, it does. You are lightest on the equator, no change at the poles.
how come i do not have gravity?
You do.
what is gravity

In 25 words or less?

Integral said:
Yes, it does. You are lightest on the equator, no change at the poles.
Even more so because the centrifugal force makes the Earth bulge out at the equator so you are further form the centre and so gravity is also less.

Integral said:
Yes, it does. You are lightest on the equator, no change at the poles.

You do.

In 25 words or less?

how do i have gravity?
sure make it 26 since your such a sweetheart

ben328i said:
how do i have gravity?
sure make it 26 since your such a sweetheart

anything with mass has gravity. Your mass is so small that its negligible. Which is why things aren't orbiting you.

Gravity=(G * m1 * m2) / (d^2)

G= 6.67300 × 10^-11
m2=mass of other thing(such as the earth) in kg.
d=distance in metres

Everything with mass also has gravity.

Everything with mass has gravity - you attract the Earth slightly, just as the Earth attracts you.

mgb_phys said:
…you attract the Earth slightly, just as the Earth attracts you.
You and the Earth, sitting in a tree…

Just incase he didnt get it in 3 posts:

"Everything with mass also has gravity"

P.S. - Everything with mass also has gravity.

Side: Everything with mass also has gravity

Note: Everything with mass also has gravity

ref:

[1] "Everything with mass also has gravity", CaptainQuasar, et al.

(Sorry, I just thought it was funny that the same thing was reposted 3 times in a row; just incase he didnt get it the first two times.)

However, "sure make it 26 since your such a sweetheart" is priceless

Last edited:
Cyrus said:
Just incase he didnt get it in 3 posts:

"Everything with mass also has gravity"

P.S. - Everything with mass also has gravity.

Side: Everything with mass also has gravity

Note: Everything with mass also has gravity

ref:

[1] "Everything with mass also has gravity", CaptainQuasar, et al.

(Sorry, I just thought it was funny that the same thing was reposted 3 times in a row; just incase he didnt get it the first two times.)

However, "sure make it 26 since your such a sweetheart" is priceless

so mass has gravity you say?

anyway, how can you prove that i have gravity?

ben328i said:
so mass has gravity you say?

anyway, how can you prove that i have gravity?
Stand on a scale.

Looks like its been answered, time to close it.

I remember doing a calculation about your first point once. Assuming several idealized things, I calculated that the difference between the force we feel at the poles compared to the equator is about 0.02m/s^2.

jhicks said:
I remember doing a calculation about your first point once. Assuming several idealized things, I calculated that the difference between the force we feel at the poles compared to the equator is about 0.02m/s^2.

If you could stand on the outside edge of Jupiter at the equator, what would the difference be? doesn't Jupiter have something like an 8 hour day?

tribdog said:
If you could stand on the outside edge of Jupiter at the equator, what would the difference be? doesn't Jupiter have something like an 8 hour day?

Everything would be different in that case because not only is Jupiter spinning faster but it's more massive and larger.

There would be relative difference between what you'd weigh at Jupiter's equator versus its poles as there is a relative difference between what you'd weigh at Earth's equator versus its poles. But because you're swinging through a tighter curve on Earth, even though it would involve slower motion than on Jupiter, I think you'd have to do all of the calculations to figure out on which planet the relative difference would be greater.

jhicks said:
I remember doing a calculation about your first point once. Assuming several idealized things, I calculated that the difference between the force we feel at the poles compared to the equator is about 0.02m/s^2.
You're off by a bit. Centrifugal acceleration is $r\omega^2$, where $r$ is the distance from the axis of rotation. At the equator, $r=6378\,\text{km}$, and at the poles, $r=0$. Using the fact that the Earth makes one revolution in one sidereal day, $6378\,\text{km} *(2\pi/\text{sidereal day})^2 = 0.034\,\text{m}/\text{s}^2$.

Just let the Google calculator does the work for you:

However, this is not the end of the story. A person at the equator is further from the center of the Earth than someone at one of the poles due to the Earth's equatorial bulge. This further reduces the gravitational attraction at the equator. The Earth's equatorial bulge is due to the Earth's rotation about its axis. You need to factor the bulge in as well if you want a full accounting of the effects of the Earth's rotation rate. This raises the effect of rotation on sensed acceleration from 0.034 m/s2 to 0.052 m/s2, or about 0.5% of the gravitational acceleration.

Last edited by a moderator:
Sorry when I gave that figure I wasn't intending to be accurate. The 1 sig fig was more or less to emphasize how small of a difference the value is relative to the pull due to gravity.

If you're within an order of magnitude, you're correct enough. ;)

## 1. Does the rotation of the earth actually affect our weight?

Yes, the rotation of the earth does have an impact on our weight. However, the effect is very small and is not noticeable in our daily lives.

## 2. How does the rotation of the earth affect centrifugal force?

The rotation of the earth does create a centrifugal force, but it is counteracted by the force of gravity. This is what keeps us grounded and prevents us from being flung off into space.

## 3. Is it possible for centrifugal force to make us lighter?

In theory, yes, centrifugal force could make us lighter. However, the effect is so small that it is negligible compared to the force of gravity. Therefore, we do not feel any lighter due to centrifugal force.

## 4. Does the speed of the earth's rotation affect the strength of centrifugal force?

Yes, the faster the rotation of the earth, the stronger the centrifugal force. However, the earth's rotation is relatively slow and the resulting centrifugal force is not significant enough to have a noticeable impact on our weight.

## 5. Can we manipulate centrifugal force to make ourselves lighter?

No, we cannot manipulate centrifugal force to make ourselves lighter. The force is a result of the earth's rotation and is not something we can control or change.

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