Infinite springs with force constants k,2 k, 4ft and I k,... respectively are connected in series. The effective force constant of the spring will be
2k
k
k /2
15 k
When the springs are connected in series, then1k′=1k+12k+14k+18k+… =1k1+12+14+18+… =1k11−(1/2)=2k k′=k/2