Hi Our teacher told us the following:F = m * v² / r = m * 4 pi² /

[physwha]

hi

Our teacher told us the following:

F = m * v² / r = m * 4 pi² / T² * r

= m * 4 pi² / k * 1 / r²

= c * m / r²

F = y * mM / r2

Why is there the k and 1 / r² and later the c?

 

[vela]

Did this have to do with one object orbiting another?

 

[physwha]

Yes, it's about the Earth around the Sun for example.

PS: I now understand the c but still not k (is it the same?) and 1 / r² :S

 

[vela]

Are you familiar with the following formula?
T = 2\pi\sqrt{\frac{r^3}{GM}}where T is the time taken for one orbit, r is the radius of the orbit, G is the gravitational constant, and M is the mass of the body being orbited.