A bag of mass M- 3 kg is hung on a hinge C by a thread length L-50cm, which is inextensible and of negligible mass. The sack, initially inclined at an angle a = 30 with respect to the vertical, it is left to oscillate freely. When the bag reaches the vertical position, it impacts with a projectile of mass m=20g. Following the perfectly inclastic collision the bag remains stationary along the vertical. a) Determine the speed of the projectile before the collision. b) In case the bullet hit the bag in the same place but with opposite speed, determine the maximum angle of the oscillations.