A spring of force constant k is cut into lengths of ratio 1 : 2 : 3. They are connected in series and the new force constant is k'. Then they are connected in parallel and force constant is k''. Then k' : k'' is
- 1 : 9
- 1 : 11
- 1 : 14
- 1 : 6
Answer
(2) 1 : 11
Solution
Force constant 1length; lengths are L6, 2L6, 3L6
k1 = 6k, k2 = 3k, k3 = 2k
Series: 1k' = 16k + 13k + 12k = 1k k' = k
Parallel: k'' = 6k + 3k + 2k = 11k
k' : k'' = 1 : 11
Answer: (2)