Is my physics quiz on confirmations correct?

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The quiz questions focus on the concepts of center of mass, centripetal force, and rotational motion. For the first question, the correct answer is B, as the center of mass may lie outside the object. The second question's correct answer is also B, indicating that the horizontal force on the ball points inward towards the center of the circle. In the third question, the correct answer is C, as bringing the dumbbells closer increases the man's rotational speed. The provided answers B, B, and C are confirmed as correct.
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Hi there, I have a multiple choice quiz that I completed for my physics class and I'm looking for confirmation on whether I'm correct or not.

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



3. 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

The answers I got are B, B and C respectively. Can anyone confirm?
 
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