A force of `6.4N` streches a vertical spring by `0.1m` The mass that must be supended from the spring so that it oscilation with a time period of `pi//4` second

Options

A. `2kg`
B. `1kg`
C. `1.5kg`
D. `2.5kg`

Answer

B

Explanation

Here, `F=6.4N, l=0.1m, T=pi//4s`
Spring factor,`k=(6.4)/(0.1)64Nm^(-1)`
Inertial factor`=` mass suspended `=`m
In S.H.M. the time period is given by
`T=2pisqrt((i n ertia fact o r)/(spri ng fact o r ))`
`(pi)/(4)=2pisqrt((m)/(64))` or `(1)/(8)=sqrt((m)/(64))` squaring both sides
`(1)/(64)=(m)/(64)` or `m=1kg`