The total momentum of a flock of identical birds could be zero only if the birds are
A. taking off from the ground.
B. flying in the same direction.
C. flying in different directions.
D. very tired and coming down to rest.
Answer:C
The total momentum of a flock of identical birds could be zero only if the birds are
A. taking off from the ground. B. flying in the same direction. C. flying in different directions. D. very tired and coming down to rest.