Choose the corect answer: After a cannonball I is fired into frictionless space , the amount of force needed to keep it going equals zero, since no force is necessary to keep it moving. twice the force with which it was fired one half the force with which it was fired.

## Step 1<br />The problem is based on Newton's first law of motion, also known as the law of inertia. This law states that an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.<br /><br />## Step 2<br />In this case, the cannonball is fired into frictionless space. This means there is no friction or any other force acting on the cannonball to change its state of motion.<br /><br />## Step 3<br />Since there is no force acting on the cannonball to change its state of motion, the amount of force needed to keep it going is zero.