Some doubts regarding rotational dynamics

AI Thread Summary
When a ball is tied to a string and rotated, the tension in the string is the only external force acting on it, which balances the gravitational force (mg) acting downward. The string creates an angle with the horizontal, ensuring that the net vertical force is zero. For an object in circular motion, the net external force acts toward the center of the circular path, providing the necessary centripetal force. The discussion highlights the relationship between tension, gravity, and circular motion dynamics. Understanding these forces is crucial for analyzing rotational dynamics accurately.
dreamz25
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a) suppose we tie a ball with a string and rotate it keeping its other end tied with one of our fingers then the only external force acting on it is the tension. Which force then cancells 'mg' acting vertically downward?

b) if a mass is rotating in a circular path then in which direction does the net external force acting on it acts?
 
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dreamz25 said:
a) suppose we tie a ball with a string and rotate it keeping its other end tied with one of our fingers then the only external force acting on it is the tension. Which force then cancells 'mg' acting vertically downward?
Not exactly sure what you are describing. But if you twirl the ball on the end of a string in a horizontal circle, the string will make an angle with the horizontal. The net vertical force will be zero.
b) if a mass is rotating in a circular path then in which direction does the net external force acting on it acts?
What do you think?
 

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