A block of 2 kg is suspended from the ceiling through a massless spring of spring constant k = 100 N/m. What is the elongation of the spring ? If another 1 kg is added to the block, what would be the further elongation ?
Given, m = 2k , k = 100 N/m
From the free body diagram...
kl - 2g = 0
⇒kl=2g
⇒l=2gk=2×9.8100
= 19.6100=0.196≈0.2m
Suppose further elongation happens when 1 kg block us added be x.
Then k (l + x ) = 3g
⇒kx=3g−2g=g=9.8N
⇒2gk=2×9.8100
=19.6100=0.098=0.1m