Answer:
29.3 rad/s
Explanation:
Moment of inertia in straight position, I1 = I
He takes 2 rotations in 1.5 second
So, Time period, T = 1.5 / 2 = 0.75 second
w1 = 2 x 3.14 / T = 2 x 3.14 / 0.75 = 8.37 rad/s
Moment of inertia in tucked position, I2 = I / 3.5
Let the new angular speed is w2.
By the use of conservation of angular momentum, if no external torque is applied, then angular momentum is constant.
L1 = L2
I1 w1 = I2 w2
I x 8.37 = I / 3.5 x w2
w2 = 29.3 rad/s