What is its deceleration?

The answer to this item is 5 m/s. An object that is decelerating is moving slower from its original velocity. The billiard ball that has an initial velocity of 15 m/s2 happened to stop after 3 seconds. To get its deceleration, we must divide the velocity by the time so it will be 15 meters per second squared divided by 3 seconds.

The answer will be 5 m/s. This means that the billiard ball is moving 5 meters per second until its movement stopped. The value is not negative as it is not moving downwards and both given variables are positive thus the result (deceleration of the object) should be positive too.