How do we calculate gravitational force when an object is inside a shell?

  • Thread starter Thread starter anhchangdeptra
  • Start date Start date
  • Tags Tags
    Shell Theorem
AI Thread Summary
To calculate gravitational force when an object is inside a shell, the shell theorem can be applied to both the inner and outer shells. When the object is within the inner shell, only the mass of the inner shell contributes to the gravitational force, while the mass above it does not affect the force experienced by the object. The gravitational force can be expressed using the formula (GMm)/r^2, where r is the distance from the object's position to the center of the shell. It's crucial to adjust the mass M to reflect only the mass of the shell that is below the object. Understanding these principles allows for accurate calculations of gravitational force in complex shell configurations.
anhchangdeptra
Messages
8
Reaction score
0
Imagine all the mass of the Earth is in a shell of a thickness of R(earth)/2. So if the object is inside the shell or outside the shell, I know I can apply the shell theorem to solve the gravitational force acting on it. But, what if the object is IN the shell, in another words R(earth)/2<r<R(earth), how do we calculate the gravitational force?
 
Physics news on Phys.org
so its like you have two shells. The object is outside one shell and inside the other. Apply the shell theorem to each one and what do you get.
 
Oh! So we only care about the smaller shell with radius= R/2. The distance from mass m to the center is r so basically we have the same formula as for an object outside the bigger shell= (GMm)/r^2 (only the r is different is the two cases)?
 
anhchangdeptra said:
Oh! So we only care about the smaller shell with radius= R/2. The distance from mass m to the center is r so basically we have the same formula as for an object outside the bigger shell= (GMm)/r^2 (only the r is different is the two cases)?
M is also different. After all, you don't care about the part of the shell above the object.
 
  • Like
Likes 1 person
Oh yes! I really forget the M. Thank you very much!
 

Thread 'Why can't Solar panels be hemispherical, or a curved strip type?'

comparing a flat solar panel of area 2π r² and a hemisphere of the same area, the hemispherical solar panel would only occupy the area π r² of while the flat panel would occupy an entire 2π r² of land. wouldn't the hemispherical version have the same area of panel exposed to the sun, occupy less land space and can therefore increase the number of panels one land can have fitted? this would increase the power output proportionally as well. when I searched it up I wasn't satisfied with...
View full post »

Similar threads

I Shell structure topological defects as substitute for dark matter
Replies
3
Views
2K
I A "continous" gravitational field formula r=0 to infinity
Replies
16
Views
594
How would shell theorem act in a hollow sphere?
Replies
8
Views
2K
Net gravitational force inside a shell
Replies
4
Views
2K
I Gravity inside an exponential mass disk
Replies
16
Views
2K
A point mass inside a spherical shell
Replies
4
Views
4K
Force between point charges at the center of two spherical shells
Replies
4
Views
2K
Electric field & force due to charged insulating hemispherical shells
Replies
12
Views
2K
Electric field for a spherical shell when r=R?
Replies
20
Views
2K
Rolling ball inside a shell problem
Replies
7
Views
3K

Hot Threads

Recent Insights

Back
Top