Question

If a spring balance holding a heavy object is released, it will read:
A) zero weight
B) more weight
C) less weight
D) same weight

Answer 1

Spring is a device that stores energy during deformation and releases the same energy when it is required. Due to its deformation behavior, it is used for measuring the weight of the object in balance equipment. . Spring obeys the principle of hooke's law.

Complete step by step answer:
Spring balance works on the principle of hooke's law. The distance extended by the spring is directly proportional to the weight of the object. Hooke's law expressed as $\sigma \propto \varepsilon ......(1)$
where $\sigma$ is the stress produced by the spring $\left( {\sigma = \dfrac{{load}}{{Area}}} \right)$ and $\varepsilon$ is the strain produced by the spring.
The weight measured by the spring balance is $w = mg......(2)$
$m$ is the mass of the object and $g$ is the acceleration due to gravity.
By equating (1) and (2) we get
$\dfrac{{load}}{{Area}}\propto \varepsilon \\\ \varepsilon \;\propto \;load......(3) \\\$
Deformation produced by the springs is directly proportional to the load carried by the spring balance.
When the heavy object holding an object is released, then there is no deformation, so it does not show more weight, less weight, and same weight because deformation is directly proportional to the load so option B, C, and D are wrong.
When the heavy object is released, then there is no deformation by the spring. Since deformation is zero, then the load subjected by the balance is also zero as per equation (3).

Hence, option (A) is correct.

Note:
When the spring extension is so large, it will be subjected to more weight and measuring the weight of the object by spring balance used to derive the hooke's law for a material subjected to load. It also shows zero deflection when spring holds a mass allowed to free fall.