a.
r = distance of each mass from the axis of rotation = 0.6 m
m = magnitude of each mass = 2 kg
v = speed of each mass = 1.1 m/s
combined angular momentum of the masses is given as
L = m v r + m v r
L = 2 m v r
inserting the values
L = 2 (2) (1.1) (0.6)
L = 2.64 kg m²/s
b.
r' = new radius  around the axis of rotation = 0.15 m
v' = new speed
using conservation of angular momentum
angular momentum after pulling arms = angular momentum before pulling arms
L' = L
2 m v' r' = 2 m v r
v' r' = v r
v' (0.15) = (1.1) (0.6)
v' = 4.4 m/s
