ACCELERATION

Acceleration of an object in motion is defined as the ratio of change in velocity and the corresponding time taken by the object i.e.

acceleration=(change in velocity)/time taken

Acceleration is a vector quantity.It is positive if the velocity is decreasing.The negative acceleration is also called retardation or deceleration.

The unit of acceleration is m s⁻²   

^{(a)Uniform acceleration.An object is said to be moving with a uniform acceleration if its velocity}

 ^{changes by equal amounts in equal intervals of time.}

^{(b)Variable acceleration.An object is said to be moving with a variable acceleration if its velocity} 

^{changes by unequal amounts in equal intervals of time.}

^{(c)Average acceleration.When an object is moving with a variable acceleration,then the average} 

^{acceleration of the object for the given motion is defined as the ratio of the total change in}

 ^{velocity of the object during motion to the total time taken i.e.,
   →}

   ^{aav =(total change in velocity)/(total time taken)}

         
<sup>The average acceleration can be positive or negative depending upon the sign of slope of 
velocity of the object in the given interval of time is zero.

(d) Instantaneous acceleration.When an object is moving with variable acceleration,then the 
object  possesses different accelerations at different instants.The acceleration of the object at a 
given instant of time or at a given points of motion,is called its instantaneous acceleration.</sup>