Practice question
Question
A train moving at 108km/h decelerates at 2m/s2 for 10s, then at 4m/s2 until it stops. What is the total time taken to stop?
Explanation
Speed: 108km/h=30m/s. As per NCERT Chapter 3, equations v=u+at, s=ut+½at², v²=u²+2as describe uniformly accelerated motion. Applying correct signs and units gives 30 m/s as the result, so option A is correct.