angular momentum, moment of force and principle of angular impul and momentum

if there are no external impulses acting on a particle

both linear momentum and angular momentum are conserved

a ball traveling on a smooth surface in a 3ft radius circle with a speed of 6ft/s. if the attached cord is pulled down with a constant speed of 2ft/s, which of the following principles can be applied to solve for the velocity of the ball when r=2ft (picture)

conversation of energy and conservation of angular momentum

select the correct expression for the angular momentum of a particle about a point

r x (mv)

the sum of the moments of all external forces acting on a particle is equal to

time rate of change of angular momentum

if a particle moves in the z-y plane its angular momentum vector is in the

x direction

if a particle moves in the x-y plane, its angular momentum vector is in the

z direction