In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods

In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are ______ respectively. 

(A) positive, negative and negative (B) positive, zero and negative (C) positive, positive and negative (D) positive, negative and zero
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Answer :

In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are positive, negative and negative respectively. 

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