# The attractive gravitational forces between two people separated by 1.5 meters

• robax25
In summary: A stack of 11 spheres of 1.5 meters in radius will reduce the gravitational force between the two objects by 10%.Treat the system as a spherical 70kg chicken and a spherical 80kg chicken (in a vacuum) ...E.g. A stack of 11 spheres of 1.5 meters in radius will reduce the gravitational force between the two objects by 10%.
robax25
Homework Statement
calculate attractive forces between you and your friend if your body weight is 80 kg and your friend weight is 70kg. The distance is 1,5m.

At which angular velocity could you spain about a common center such that the centrifugal forces don't drive you away from each other?

what is the maximum force if the distance was zero?
Relevant Equations
F= Gm1M2/r²
v=ω * r
F= Gm1m2/r² = 1.667*10^-7 N.
I don't understand How to calculate angular velocity?

PhDeezNutz
Possibly start by finding the distance from each of you to the common center. Where will the center be?

0.75m. Do you think that centrifugal force is 1.667*10^-7 N?

Centrifugal force is F= mv²/r,
F= mω²r.

robax25 said:
0.75m. Do you think that centrifugal force is 1.667*10^-7 N?

Centrifugal force is F= mv²/r,
F= mω²r.
If the two of you were to spin about that center, would your center of mass be moving?

Does that suggest that some other center might be a more proper choice?

robax25 said:
Homework Statement:: calculate attractive forces between you and your friend if your body weight is 80 kg and your friend weight is 70kg. The distance is 1,5m.

At which angular velocity could you spain about a common center such that the centrifugal forces don't drive you away from each other?

what is the maximum force if the distance was zero?
Relevant Equations:: F= Gm1M2/r²
Isn't this formula only valid for point masses or spherically symmetric objects? That said, I assume it's what you are supposed to use.

jbriggs444 said:
If the two of you were to spin about that center, would your center of mass be moving?

Does that suggest that some other center might be a more proper choice?
yes. Center of mass will move.

PeroK
robax25 said:
yes. Center of mass will move.
That requires an external force acting on the two-body system, doesn't it?

PeroK said:
Isn't this formula only valid for point masses or spherically symmetric objects? That said, I assume it's what you are supposed to use.
I need to calculate centrifugal force and angular velocity.
PeroK said:
That requires an external force acting on the two-body system, doesn't it?
yes. It does.

robax25 said:
I need to calculate centrifugal force and angular velocity.

yes. It does.
What provides the external force to move the centre of mass?

As far as, I understand that there is only gravitational force acts on them .I mean F= mg if they Spain, the force will be same. Obviously, the F=Gm1m2/r² will not be the force that I have thought the centrifugal force.

robax25 said:
As far as, I understand that there is only gravitational force acts on them .I mean F= mg if they Spain, the force will be same. Obviously, the F=Gm1m2/r² will not be the force that I have thought the centrifugal force.
Right. Only gravity. Since that is an internal force rather than an external force, momentum must be conserved. The center of mass cannot move.

It follows that the two objects cannot both circle about their geometric center. What center can they circle about so that the center of mass does not move?

PeroK said:
Isn't this formula only valid for point masses or spherically symmetric objects? That said, I assume it's what you are supposed to use.
Out of interest, I modeled the bodies as stacks of 11 perfect spheres of various radii, roughly forming the shape of people.
It cut the gravitational attraction by about 10% compared with a single sphere for each.

Last edited:
PeroK and Bandersnatch
haruspex said:
Out of interest, I modeled the bodies as stacks of 11 perfect spheres of various radii, roughly forming the shape of people.
It cut the gravitational attraction by about 10% compared with a single sphere for each.
Treat the system as a spherical 70kg chicken and a spherical 80kg chicken (in a vacuum) ...
E.g.

wrobel

## What is the attractive gravitational force between two people separated by 1.5 meters?

The attractive gravitational force between two people separated by 1.5 meters is extremely small, on the order of 10^-6 Newtons. This force is a result of the gravitational pull between the masses of the two individuals, which is determined by their respective masses and the distance between them.

## How does the attractive gravitational force between two people change with distance?

The attractive gravitational force between two people follows an inverse square law, meaning that as the distance between them increases, the force decreases exponentially. This means that the force will be stronger at 1 meter compared to 1.5 meters, and even stronger at 0.5 meters.

## Can the attractive gravitational force between two people be felt?

No, the attractive gravitational force between two people is too small to be felt by humans. It is only significant on a large scale, such as between planets or stars.

## What factors can affect the attractive gravitational force between two people?

The only factors that can affect the attractive gravitational force between two people are their respective masses and the distance between them. Other factors, such as the environment or the presence of other objects, do not have a significant impact on this force.

## Is the attractive gravitational force between two people the only force acting on them?

No, there are many other forces at play between two people, such as electromagnetic forces, friction, and air resistance. These forces can have a much greater impact on the individuals compared to the small attractive gravitational force between them.

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