This is not a homework question. An adult exerts a horizontal force on a swing that is suspended by a rope of length L, holding it at an angle θ with the vertical. The child in the swing has a weight W and dimensions that are negligible compared to L. The weights of the rope and of the seat are negligible. Then the adult releases the swing from rest. as the swing passes through its lowest point, does the system have rotational kinetic energy also? (<-- this is my own question) My teacher pulled up this question and ask everyone solve for v (when it reach the bottom)? Is it like : initial Translational K + initial Potential U = final Translational K + final Potential U OR : intial translational K + initial Potential U = final Translational K + final rotation K + final Potential U ??????? At first, everyone thought the first way. BUt my teacher pull up the second thought, and it make perfect sense. So, I look up the question online, and all scoring guidelines solve it without rotational kinetic energy. WHO IS RIGHT AND WHO IS WRONG?