An object is dropped from rest at a height of 150 m and simultaneously another object is dropped from rest at a height 100 m. What is the difference in their heights after 2 s if both the objects drop with same accelerations? How does the difference in heights vary with time?
Show answer
Initial difference in height = (150 – 100) m = 50 m Distance travelled by first body in 2 s = h 1 = 0 + g (2)2 = 2 g Distance travelled by another body in 2 s = h2 = 0 + g (2)2 = 2 g After 2 s, height at which the first body will be = h 1′ = 150 – 2 g After 2 s, height at which the second body will be = h 2′ = 100 – 2 g Thus, after 2 s, difference in height = 150 – 2 g – (100 – 2 g) = 50 m = initial difference in height Thus, difference in height does not vary with time. ANSWERS 129 1 2 1