Newtons law of gravity states that the gravitational attraction F between two bodies is proportional

to 1 over the square of the distance d between their centers.
(a) Using k as the constant of proportionality, express F as a function of d.
(b) What happens to F near the pole at d = 0?
(c) Explain in practical terms the meaning of the pole at d = 0.

3 answers

F = k/d^2

b) undefined because zero denominator (gets very big as d gets small)

c) If an object has mass, it also has size. It is impossible to get d = 0 because the objects bump before their centers of gravity collide. So, although the force can become large, it does not really approach infinity in practice (although bringing two neutrons together might be pretty interesting :)
Thank you so much
:)
You are welcome.