(1) When a body is suspended from two light springs separately. The time period of vertical oscillations are T₁ and T₂ respectively.

When these two springs are connected in series and the same mass m is attached at lower end and then for series combination

When these two springs are connected in parallel and the same mass m is attached at lower end and then for parallel combination

(2) The pendulum clock runs slow due to increase in its time period whereas it becomes fast due to decrease in time period.

(3) If infinite spring with force constant respectively are connected in series. The effective force constant of the spring will be

(4) If

are two S.H.M. then by the superimposition of these two S.H.M. we get

(5) If a particle performs S.H.M. whose velocity is at a  distance from mean position and velocity  at distance(x)