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Question:

A bob of mass, m, attached to an inextensible string of length, l, is suspended from a vertical support. The bob rotates in a horizontal circle with an angular speed, ω rad/s, about the vertical. About the point of suspension: angular momentum changes both in direction and magnitude, angular momentum changes in direction but not in magnitude, angular momentum is conserved, angular momentum changes in magnitude but not in direction

angular momentum is conserved

angular momentum changes in magnitude but not in direction

angular momentum changes in direction but not in magnitude

angular momentum changes both in direction and magnitude

Solution:

L changes in direction not in magnitude. Magnitude of L = mωl upwards, which remains the same.