A spring can be used to determine the mass m of an object in two ways : (i) by measuring the extension in the spring due to the object; and (ii) by measuring the oscillation period for the given mass. Which of these methods can be used in a space-station orbiting Earth ?

In a space station orbiting Earth, objects are in a state of free fall, creating a microgravity environment. A spring balance measures mass indirectly by measuring weight, which is the gravitational force acting on an object [1]. In microgravity, the effective weight is zero, so the spring will not extend under the static load of a mass, making the extension method unusable [1]. However, the oscillation method relies on the inertial mass of the object. The period of oscillation (T) for a mass-spring system is given by T = 2π√(m/k), where 'm' is the mass and 'k' is the spring constant. Since inertia is an intrinsic property of matter and independent of gravity, the period of oscillation remains measurable in space [2]. NASA has utilized this oscillating spring-mass principle to determine the mass of astronauts and equipment in orbit [2].

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 73
2. [2] https://ntrs.nasa.gov/api/citations/19690009777/downloads/19690009777.pdf