A small 0.1-kg particle is given a velocity of 2 m/s on the horizontal x-y plane and is...

A small 0.1-kg particle is given a velocity of 2 m/s on the horizontal x-y plane and is guided by the fixed curved rail. Friction is negligible. As the particle crosses the y-axis at A, its velocity is in the x-direction, and as it crosses the x-axis at B, its velocity makes a 60 angle with the x-axis. The radius of curvature of the path at B is 500 mm. Determine the time rate of change of the angular momentum H₀ of the particle about the z-axis through O at both A and B.