Question

A spring balance has a scale that reads from $0$ to $50\, kg$. The length of the scale is $20\,cm$. A body suspended from this balance, when displaced and released, oscillates with a period of $0.6\, s$. The weight of the body is

• A. 192 N
• B. 129 N
• C. 912 N
• D. 219 N

Answer 1

Answer: (D)

219 N

Answer 2

Using, $k = \frac{F}{l} = \frac{mg}{l}$, we get $k = \frac{50 \times 9.8}{0.2} = 2450 \, N \, m^{-2}$ Time period, T =$2 \pi \sqrt{\frac{M}{k}}$ i.e. 0.60 = $2 \pi \sqrt{\frac{M}{2450}}$ i.e. M = 22.34 kg Weight of the body = 23.3 $\times$ 9.8 =218.9 N