Practice question
Question
A truck moving at 15m/s decelerates uniformly and stops after 30m. How long does it take to stop?
Explanation
Use v2=v02+2ax to find a: 0=(15)2+2a(30)⇒0=225+60a⇒a=−3.75m/s2. 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 4 s as the result, so option C is correct.