Question

the definition of velocity and acceleration

Answer 1

 Acceleration =  It has be define as change in velocity of an object in unit time.
Velocity = it is the speed of an object moving in a definete direction .

Answer 2

velocity: it is discplacement per unit time. ( i'm talking about displacement in motion ,displacement is shortest path from final to initial position). It is same as speed but , speed is distance per unit time. The SI units of velocity are same as of speed. It is a vector quantity and thus shows direction with magnitude of displacement.                   
                                                                                                 
 Acceleration: it defines the rate of change of motion (speed/velocity) per unit time, it can be positive or negative ,if acceleration is applied against to the direction of motion the acc. will be negative and if in direction of motion then would be positive. It is also a vector quantity. SI unit is m/s^2 .
 
 speed = distance/time 
 velocity= displacement/time              
acceleration=  change in velocity / change in time
                            
                                                  THANK YOU