A body attached to a spring balance weighs 10 kg on the Earth. The body attached to the same spring balance is taken to a planet where gravity is half that of the Earth. The balance will read

A spring balance measures weight, which is the gravitational force acting on an object, rather than its intrinsic mass [2]. While mass remains constant regardless of location, weight is directly proportional to the acceleration due to gravity (W = mg) [3]. Spring balances are typically calibrated on Earth to display mass units (kg) based on Earth's standard gravity [2]. If a body weighs 10 kg on Earth, the spring is stretched by a force corresponding to 10 kg × g. On a planet where gravity is half that of Earth (0.5g), the gravitational force (weight) acting on the same mass will be halved. Consequently, the spring will stretch only half as much, and the scale—calibrated to Earth's gravity—will indicate a reading of 5 kg.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 75
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 73
3. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 9: The Amazing World of Solutes, Solvents, and Solutions > A step further > p. 142