We were never given an explanation in class. I remember in my high school physics class last year, our teacher told us this is true but never showed us why. All he said was that you had to integrate a function relating distance to mass, and the result would be a net force of 0 anywhere inside the hollow sphere Can someone help me out with this? Maybe not tell me the answer, just inform me on what equation to work with, as i enjoy figuring things out on my own if possible. Thanks, guys!