Respuesta :
To answer this question, we must bear in mind the following considerations that are mentioned in the statement:
The cannon balls are identical and shoot with the same force
The force acting on the cannonball increases with the length of the hole.
You want to know which cannon will have the least momentum on the ball.
Then, the force on the ball increases as the barrel length increases and the impulse depends on the magnitude of the force, then, the cannon that will have the minimum impulse will be the 1 meter one.
The answer is option B.