Speed By Time?

Anbu, Acceleration is Rate of change of velocity. Speed /time has no meaning, though it has the units of acceleration.
The problem with velocity is that as #-Link-Snipped-# said it is a vector. It has both a value and a direction.

The velocity changes if either speed or direction or both change.

It is important to have this clear. Consider an object, say the Earth spinning around the Sun. It takes the same one year for a full orbit. The speed of the earth in its orbit (in terms of km/sec) does not change. The Sun has a gravitational pull on Earth trying to pull it into the Sun.
Why does not the Earth fall into the Sun?
Because though the speed of the Earth in its orbit is fixed, its direction is continuously changing at the rate of about one degree/day. So, though its speed is constant the Velocity is changing.
Acceleration = (change in velocity/time), which means that Earth experiences an acceleration away from the Sun. The value of this exactly matches the acceleration due to Sun's gravity pulling the Earth towards the Sun . The two cancel and so Earth is in a stable orbit.[/quote]