"Understand that, for a point outside a uniform sphere, the mass of the sphere can be considered a point mass." This is one of the "learning outcomes" in the A level Course. Here are my questions related to it. 1.) What is meant by point masses? (A definition will do) 2.) Why do we consider point masses? What's the problem with dealing a uniform spherical objects as normal spherical objects? 3.) What are the limitations for this consideration? When this consideration can't be used? 4.) They are dealing with "point outside a uniform sphere". Why is the consideration not suitable when the point is inside the uniform sphere?