A bullet of mass 0.01kg is fired in to sand bag of mass 0.49kg longing from a tree the sand bag with the bullet at 10m/s find A , the momentum after the collision.

B, the momentum before the collision
C, the velocity of the bullet

The momentum before and after is the SAME. (First Law) 0 .10

mass after collision = 0.01 + 0.49 = 0.50 kg
as you know the momentum remains 0.10 kg m/s
so
0.10 = 0.50 * v
v = 0.20 m/s

after the collision

A) The momentum after the collision is 0.1 kg m/s.

B) The momentum before the collision is 0.01 kg m/s.

C) The velocity of the bullet after the collision is 0 m/s.