A hollow, thin-walled sphere of mass 12.0kg and diameter 47.0cm is rotating about an axle through its center. The angle (in radians) through which it turns as a function of time (in seconds) is given by ?(t)=At2+Bt4, where A has numerical value 1.10 and B has numerical value 1.50.

1. At the time 4.00s , find the angular momentum of the sphere.

2. At the time 4.00s , find the net torque on the sphere.