Question

When a mass is hung from a light spring, the spring extends by 10 cm. If the mass is pulled down and let go, it executes S.H.M. with a time period (g = 10 m/s²) ____________.

Options

• `2pi"s"`

• `pi/5 "s"`

• `pi/10 "s"`

• that cannot be found as the mass of the body and the force constant of the spring are not given

Answer 1

When a mass is hung from a light spring, the spring extends by 10 cm. If the mass is pulled down and let go, it executes S.H.M. with a time period (g = 10 m/s²) 

`pi/5 "s"`.

Explanation:

T = 2π  `sqrt(m/k)` and mg = kx₀

or `m/k` = `"x"_0/g` = `(10 xx 10^-2)/10` = `1/100`

`therefore "T" = 2pi  sqrt(1/100) = pi/5"s"`