Why can velocity ever equal zero?
The first answer has it completely wrong. Velocity can be zero. Velocity has a speed and a direction … but it can only have a direction if the velocity is not zero. The direction of velocity tells you which way the object is moving. But if the object has zero velocity, it is not moving at all. It is just sitting there. And you can’t give that a direction because it is going nowhere. Acceleration tells you, not whether the object is moving, but whether the object is speeding up or slowing down. If an object has zero acceleration, you can not deduce whether the object is moving or not. An object sitting there (with zero velocity) has zero acceleration as it is not speeding up or slowing down. But an object which is moving at a constant velocity (i.e. speed not changing) also has zero acceleration.
