Two identical blocks `A` and `B` connected by massless string, are placed on a frictionless horizontal plane. A bullet havig the same mass, moving with speed `u` strickes block `B` from behind as shown. If the bullet gets embedded into block `B` then find
a. the velocity of `A,B,C` after collision.
b. impulse on `A` due to tension in the string,
c. impulse on `C` due to normal force of collision,
d. impulse on `B` due to normal force of collision.