Question Detail
Question
An object does free fall and it takes 60 m distance during last 2 seconds of its motion. Find the height it is dropped (g = 10 m/s²).
Correct Answer
Option C is the correct answer.
Detailed Explanation
Let total time be T. Distance in last 2 s = total distance - distance in (T-2) s: ½gT² - ½g(T-2)² = 60. ½×10[T² - (T² - 4T + 4)] = 5[4T - 4] = 20T - 20 = 60 → 20T = 80 → T = 4 s. Total height = ½×10×16 = 80 m.
Hint
Use s = ½gt² and set up equation for last 2 seconds.