Speed is called a scalar quantity and velocity is a vector quantity. You need to have both velocity and time to calculate acceleration. You can calculate the acceleration of an object from its change in velocity and the time taken.
Acceleration is the rate of change of velocity with time.
Many people confuse acceleration with velocity or speed. Acceleration of Acceleration of Acceleration of relative to Equations 5 and 6 are the general expressions for the radial and tangential components of relative acceleration. The standard unit of measure is meters per second or ms. Velocity is not exactly the same as speed.