The angular momentum of a system of particles is not conserved:

$A$ person is rotating on a rotating table with their arms held down. Suddenly,they spread their arms out. What happens to their angular momentum?

Two small beads are initially at $A$ on an equilateral triangle made of uniform wires. The triangle is rotated about the vertical axis $AO$. The beads are released from rest simultaneously and slide down along $AB$ and $AC$ respectively (as shown in the figure). Which quantities are conserved as the beads slide down? (Friction is negligible)

An equilateral triangle $ABC$ is made of a uniform wire. Two identical beads are initially at $A$. The triangle is set to rotate about a vertical axis $AO$. The beads are then released simultaneously from rest to slide down along $AB$ and $AC$. Neglecting friction,which quantities are conserved as the beads slide down?

When a dancer pulls their arms inward while spinning on ice,they spin faster. This is due to:

If the torque applied on a particle is zero,then its angular momentum will be: