A stone falls freely under gravity. It covers distances h1, h2 and h3 in the first 5 seconds, the next 5 seconds and the next 5 seconds respectively. The relation between h1, h2 and h3 is
- h2 = 3h1 and h3 = 3h2
- h1 = h2 = h3
- h1 = 2h2 = 3h3
- h1 = h23 = h35
Answer
(4) h1 = h23 = h35
Solution
Starting from rest, s = 12gt2
h1 = 12g(5)2 = 25g2
h1 + h2 = 12g(10)2 = 100g2
h2 = 75g2
h1 + h2 + h3 = 12g(15)2 = 225g2
h3 = 125g2
h1 : h2 : h3 = 1 : 3 : 5
h1 = h23 = h35
Answer: (4)