A spring balance has a scale that reads `0` to `20kg`. The length of the scale is `10cm`. A body suspended from this balance, when displaced and released, oscillates with period of `(pi)/(10)s`. The mass of the body is

Options

A. 2.45 kg
B. 4.9 kg
C. 9.8 kg
D. 19.6 kg

Answer

B

Explanation

Mg = kx
`20 xx 9.8 = k xx 0.1`
k = 1960
`T = 2pi sqrt((m)/(k))`
`(pi)/(10)=2pi sqrt((m)/(1960))rArr (1)/(400)=(m)/(1960)`
`rArr m = (1960)/(400) = 4.9 kg`