(a) If the spring constant in a massspring system is halved, the new period is (1) 2,...

Question:

(a) If the spring constant in a mass–spring system is halved, the new period is (1) 2, (2) √2, (3) 1/√2, (4) ½ times the old period. Why?
(b) If the initial period is 2.0 s and the spring constant is reduced to 1/3 of its initial value, what is the new period?