# Is there is any change in time period if it is done inside accelerating lift?

1. Jan 12, 2012

### vkash

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)] ).

(recently updated to firefox 9. it is not responding to spelling mistake so if i have done any mistake then please ignore that)

Last edited: Jan 12, 2012
2. Jan 12, 2012

### BruceW

I'm assuming the acceleration of the lift is meant to be constant with time? In this case, I think you have got all the answers correct :) One spelling mistake though - you've written dqrt, but I think you mean sqrt (i.e. square root).

3. Jan 13, 2012