I have 3 simple (for most people on this forum) multiple choice questions that I need help with. 1.The centre of mass of an object... A. Must always lie outside the object, at a point where there is no mass. B. May lie outside the object, at a point where no mass is. C. Must always lie within the mass of the object 2. Consider a ball on the end of a string being whirled in a horizontal circle. The horizontal force acting on the ball points... A. outwards, away from the centre of the circle B. inwards, towards the centre of the circle C. ... nonsense. There is no force at all on the ball A man is standing on a turntable holding a dumbell in each of his outstretched hands. He is rotating at 1 rev/s. If he now brings his hands in close to his chest, A. his rotational speed decreases B. his rotational speed is unchanged C. his rotational speed increases If you could please explain the answer to each question I would be grateful, I'm having issues with rotational motion. Thanks!!