1. The problem statement, all variables and given/known data Q1> there is a cube like jar of water kept at the surface of a lift which is moving with an acceleration of a in upward direction. jar is filled with water. There is a cubical block of wood floating on it's surface. It is slightly pressed and released. find the time period of the Simple harmonic motion.(viscosity of liquid is zero) Q2> A spring is attached to ceiling in lift will it's time period(of oscillations) change with acceletation of life(I think no). Q3>A pendulum is attached to ceiling will it's time period vary with acceleration.(I think yes T=2πsqrt(l/g)) After all i come to conclusion that "it is mixed one. I mean if it is inside a lift it may or may not have same time period as it had" 2. Relevant equations Archimedes principle and Simple equations of SHM. 3. The attempt at a solution let me say after slight push it's mean position is displaced by x0. After a distance x below x0 net force acting on the wooden block is dAx(g+a). here d is density A is base area of block and g is acceleration due to gravity. F=dAx(g+a) =mω2x (m is mass of block) from here T(time period)=2πdqrt(m/[dA(g+a)] ). IF i am wrong somewhere then please alert me. (recently updated to firefox 9. it is not responding to spelling mistake so if i have done any mistake then please ignore that) thanks for reading...... waiting for ur valuable reply..