Question

When velocity becomes negative?

Answer 1

Observe that the object below moves in the negative direction with a changing velocity. An object which moves in the negative direction has a negative velocity. If the object is speeding up then its accelerationvector is directed in the same direction as its motion (in this case, a negativeacceleration).

Answer 2

THEN THE ACCELERATION OF OBJECT BECOME NEGATIVE .

IT MEANS NEGATIVE ACCELERATION.