# Day 96 – Universal Gravitation

Physics 11 – And then there was the dreaded Universal Gravitation….  Why dreaded?  Despite my best efforts, students have a lot difficulties manipulating this equation. So many variables, so few numbers.  I generally find that students have a pretty fuzzy idea of algebraic manipulation.  They know some rules to follow (“if you have 4x, divide both sides by 4 to get rid of the 4”), but are pretty unclear on the mathematical underpinnings.  I looked at my son’s Math 9 textbook and I could see why this is the case.  I *think* that it would help to develop some understandings like: “the variable term will have a coefficient in front of it. Use the associative property to separate the coefficient and the variable, then multiple the term by the reciprocal of the coefficient so that the coefficient is 1.”

Other people may see the above as being too prescriptive or wordy, or not easily understood by students.  However, if a few of these steps are deliberately practiced, I would hope that the methodology would become clear and make sense.