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**srirahulan** A train start to move from rest and then travel its first part with constant acceleration of $\displaystyle f_1$then travel the second part of the constant velocity of V then travel the third part of the constant **deceleration** of $\displaystyle f_2$ then it comes to rest.So draw a velocity - time curve and it travel constant velocity with the $\displaystyle \frac{4}{3}t $ of the total time and the average speed of the total travelling is **KV.so find out the value of k? so please give me the ideas to do that.**