1. The problem statement, all variables and given/known data My textbook says that internal forces have no effect on an object's motion and that external forces are required to change the motion of an object. But, we looked at an expirement where a raw egg was spun and then stopped. After being stopped, it went back to spinning because the egg yolks inside the shell resisted the change in motion due to inertia and kept moving, causing the egg shell to begin rotating again. Isn't this an example of an internal force affecting the motion of an object? This doesn't allign with what my textbook said. 2. Relevant equations Newton's First Law 3. The attempt at a solution I have no clue.