What is Weight?

The weight of an object is defined as the measure of the amount of force that acts on mass because of the pull of gravity. Weigh is the measure of force. Therefore, Weight will vary depending on the location.

The earth attracts every item with a force that is proportional to the object’s mass (m) and acceleration due to gravity (g).  It is a vector quantity as it got the magnitude and direction toward the Earth’s center or other gravity.

The SI unit of weight is Newton, which is the same as the SI unit of force (N) and it is measured using a spring balance. A spring balance is shown in the image below.

The general properties of mass can be summarised as,

• Weight of a body can be zero if the gravity associated in any case is zero such as in the case of space.
• Weight is a vector quantity as it has both magnitude and direction.
• Weight of a body changes with the change in its location.
• Spring balance is generally used to measure weight. 
• The SI unit of weight is Newton.

Acceleration Due to Gravity (g)

Whenever an object falls toward the earth, it experiences acceleration. The earth’s gravitational force is responsible for this acceleration. This acceleration is known as acceleration due to gravity. It is denoted by g. The unit of g is m s^–2, which is the same as the unit of acceleration. The formula to calculate g is given as follows:

g = GM/R²

where, 
G is Universal Gravitational Constant (G = 6.67 × 10^-11 Nm²/Kg²)
M is the mass of the Object on which we are calculating g.
R is the radius of the Object.

Mass and Weight are commonly used in the same manner by the general masses but there are differences between both Mass and Weight, where Mass is the measure of Inertia unlike Weight which is a measure of force acting on a body towards the heavy body. But yet still many people use these two terms interchangeably.

As we know that to change the speed or direction of an object, a force is required. If you drop anything from a great height, it will fall towards the earth’s surface. The planet revolves around the Sun and the moon revolves around the earth. There must be some force operating on objects, planets, and other celestial bodies. Isaac Newton noted that the same force is responsible for all these. This force is called gravitational force.