After a cannonball is fired into frictionless space, the amount of force needed to keep it going equals

The  amount of force needed to keep it going equals to 0 N

The following information should be considered:

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0 N

Explanation:

According to Newton's first law of motion, an object in motion stays in motion until acted upon by an unbalanced force.  With no friction in space to unbalance the cannonball, it will continue to keep going.

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.