Practice question

Given: A car moving at 25 m/s decelerates uniformly to rest over 62.5 m . What is the time taken to stop? These values define the system as per NCERT data. Formula: Use v² = v_0² + 2 a x to find a : 0 = (25)² + 2 a (62.5) Rightarrow 0 = 625 + 125 a Rightarrow a = -5 m/s². This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Then, v = v_0 + a t : 0 = 25 - 5 t Rightarrow t = 5 s . The time taken is 5 s . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.