Answer to Question #94708 in Mechanics | Relativity for iv

Question

why do we need to find cos(theta) why can we not just find (d) and plug that into the gravational force equation

Answer 1

Write the gravitational force equation:

$$F=G\frac{m_1m_2}{d^2},$$

where $d$ - distance between centers of mass of objects 1 and 2 with corresponding masses. We just find that distance and plug that into gravitational force equation. Maybe you will need a cosine of angle between a very small object and a certain point of big planet in the following situation. In that case,

$$d=L\space\text{cos}\theta.$$