Question

A force of 6.4 N stretches a vertical spring by 0.1 m. The mass that must be suspended form the spring so that is oscillates with a time period of $\left(\pi /4\right)$ sec is

• A. $\left(\pi /4\right)$kg
• B. 1 kg
• C. $\left(1/\pi \right)$ kg
• D. 10 kg

Answer 1

The correct option is B 1 kg

Spring force=$Kx$

$6.4=K\times 0.1$

$K=64$

$T=2\pi \sqrt{\frac{K}{M}}$

$\frac{\pi }{4}=2\pi \sqrt{\frac{64}{M}}$

$M=1Kg$