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A weighing machine consists of a 2 kg pan resting on a spring. In this condition, with the pan resting on the spring, the length of the spring is 200 mm. When a mass of 20 kg is placed on the pan, the length of the spring becomes 100 mm. For the spring, the undeformed length L and the spring constant k (stiffness) are
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- L = 220 mm, k= 1862 N/m
- L = 210 mm, k= 1960 N/m
- L = 200 mm, k = 1960 N/m
- L = 200 mm, k= 2156 N/m
Correct Option: B
Let initial length is δ without load, and stiffness is k
∴ 2g = k(δ – 0.2) ...(i)
22g = k(δ – 0.1) ...(ii)
Solving equations (i) and (ii), we get
δ = 210 mm and k = 1960 N/m
