Question

when will you say that a body is in (1)uniform accelertion (2)non uniform acceleration

Answer 1

Uniform Acceleration:  Eg:- you are riding a cycle with the velocity of 10 m/s . after 30s, you change your velocity from 10 m/s to 20 m/s. Again after the next 30s, you change your velocity from 20 m/s to 30 m/s. 

So, This change of velocity in unit time is known as uniform acceleration.
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Non- uniform acceleration: Eg:- you are riding a cycle with the velocity of 10 m/s . after 30s, you change your velocity from 10 m/s to 25 m/s. Again after the next 30s, you change your velocity from 25 m/s to 30 m/s. 

So, unequal change of velocity per unit time can be defined as non-uniform accelaration.