A spring of force constant k is cut into two pieces such that one piece is double the length of the other. Then the long piece will have a force constant of:

Options

A. `(2//3)k`
B. `(3//2)k`
C. `3k`
D. `6k`

Answer

B

Explanation

for a spring `k prop 1/l`
`1/k_(1)+1/k_(2)=1/k,`
`:. 1/(2k_(1))+1/k_(2)=1/k {:[(l_(2)=2l_(1)),(":."k_(2)=k_(1)/2)]:}`
`rArr k_(2)=3/2k`