A pupil measured the weight of an apple of mass 0.2 kg using a spring balance and got a reading of 2 N - Junior Cycle Science - Question a - 2006

Weight and mass are two distinct concepts in physics:

1. Weight:

   • Weight is the force acting on an object due to gravity. It depends on the gravitational field strength at the object's location. The formula for weight is given by:

   $w = m imes g$

   where:

   • $w$ is the weight,
   • $m$ is the mass of the object, and
   • $g$ is the acceleration due to gravity (approximately 9.81 m/s² on Earth).
   • Therefore, the weight of the apple, when measured with the spring balance, is 2 N, which indicates the force of gravity acting on it.

2. Mass:

   • Mass is a measure of the amount of matter in an object and is constant regardless of the object's location. It is measured in kilograms (kg). Mass represents the object's resistance to being accelerated when a force is applied.
   • In this case, the apple has a mass of 0.2 kg, which means it contains a specific amount of matter, unaffected by the pull of gravity.