Question

A spring of natural length $80cm$ with a load has a length of $100cm$. If it is slightly pulled down and released its period will be

• A. $3$ s
• B. $0.88$ s
• C. $0.81$ s
• D. $2$ s

Answer 1

Answer: (B)

$0.88$ s

$x=20$
$kx=mg$
$2\times {10}^{-2}=\frac{m}{k}$---(1)
$T=2\pi \sqrt{\frac{m}{k}}$
$\frac{m}{k}=2\times {10}^{-2}\left(frome{q}^n\right(1\left)\right)$
$\therefore T=2\pi \sqrt{2\times {10}^{-2}}$
$T=0.88sec.$