Question

can a body have zero velocity but non zero acceleration ?​

Answer 1

YES. It is possible. But it is only possible for a moment. And what is a moment? It is a brief, immeasurable period whereby something happens.

Imagine you throw a ball in the air. It goes up and comes back down. When you throw it up, it has a positive velocity and a negative acceleration (it isn’t speeding up). As it hits apogee (its highest point), it has zero velocity and an acceleration equal to 9.8 m/s^2 directed toward the earth. It is at this moment that the body has negative acceleration yet no velocity.