# Analogy between satelite orbit and mass oscillating through earth

1. Mar 28, 2014

### Ezio3.1415

The period of a satellite revolving around the earth earth at surface height is equal to the period of any mass thrown through a hole of the earth(which gains a simple harmonic motion)...

It seemed really interesting to me...

Why both of these periods are same?

T=2 π √(R/g)

2. Mar 28, 2014

### A.T.

You can decompose the circular orbit into two simple harmonic motions in two dimensions. The gravitational force component in each dimension is proportional to the position along that dimension. The same proportional relationship exists along a radial line in a uniform mass sphere.

Last edited: Mar 28, 2014
3. Mar 28, 2014

### dauto

That's only true if you assume the earth's density is uniform. That's not quite correct.

4. Mar 29, 2014

### Ezio3.1415

AT Yes,but we are doing another analogy to explain this analogy... I thought of it at first but assumed their could be another approach to explain this incident... It just seems so interesting to me...

Dauto Yes... That's why we have to assume that the earth is a uniform mass sphere...