How to calculate weight in kg?

Calculating Weight on Earth: A Simple Conversion

We often use the terms “weight” and “mass” interchangeably, but they represent distinct physical quantities. Mass, measured in kilograms (kg), is a measure of the amount of matter in an object. Weight, on the other hand, is a measure of the force exerted on that object by gravity. While mass remains constant regardless of location, weight changes depending on the gravitational pull.

On Earth, a convenient relationship exists between mass and weight. The force of gravity at the Earth’s surface is relatively constant, allowing for a straightforward calculation. To find an object’s weight in Newtons (N), the standard unit of force, simply multiply its mass in kilograms by a constant value: 9.8.

The Formula:

Weight (in Newtons) = Mass (in kilograms) × 9.8

Example:

A person with a mass of 70 kilograms would have a weight of:

70 kg × 9.8 N/kg = 686 N

This calculation yields the force exerted on the person by Earth’s gravity. While this conversion is useful for everyday calculations on Earth, it’s crucial to remember that this relationship only holds true in the vicinity of the Earth’s surface. On other celestial bodies, with different gravitational forces, the conversion would be different. For instance, on the Moon, the gravitational pull is significantly weaker.