Question

how can velocity increase if the sign of velocity and acceleration are opposite

Answer 1

no it can not be increased. if you are talking about magnitude. if you are talking about the value with sign

then take velocity negative and acceleration positive . it works

Answer 2

Hey mate..here is your answer..!!!!

If the velocity and acceleration are in the same direction (both have the same sign - both positive or both negative) the object is speeding up. If the velocity and acceleration are in opposite directions (they have opposite signs), the object is slowing down.

Hope it helps..mark me as the brainliest