My child, Naomi, was working on a homework problem in their Astronomy for non-science majors class in college. They texted me about it.
The problem involved the gravitational force between the Sun and Earth and between the Sun and Mars.
The problem, which I won’t go into here unless someone wants me to, got me to thinking. What IS the gravitational force between the Sun and the Earth? It can’t be that hard to calculate, right? It is some sort of application of the “inverse square law”, right?
So I looked up Newton’s gravitational attraction equation for the gravitational attraction between any two objects. It is an application of Newton’s second law of motion, Force = mass * acceleration.
The equation is F = G ((Mm)/r^2)
The equation is not hard to do with pencil and paper. The hardest part is remembering how to multiply and divide using scientific notation. The second hardest part is keeping the complicated units of each value straight.
Here it is.
View attachment 629524
So, anybody who knows middle school math can run this equation.
Thank you, Sir Isaac!