Three masses `700g` and `500g` and `400g` are suspended at the end of a spring as shown and are in equilibrium. When the `700g` mass is removed the system oscillates with a period of `3` second. when the `500gm` mass is also removed it will oscillates with a period of

Options

A. `1s`
B. `2s`
C. `3s`
D. `sqrt((12)/(5))s`

Answer

B

Explanation

When mass `700gm` is removed, the left out mass `(500 +400) gm `oscilates with a particle of `3sec`M
`:. 3 = t = 2 pisqrt(((500 + 400))/(k))`….(i)
When `500g` mass is also removed the left mass is `400gm`
`:. t'= 2pisqrt((400)/(k))`….(ii)
`rArr (3)/(t') = sqrt((900)/(400)) rArr (3)/(t') = sqrt((900)/(400))`