Question

Force. It can be said that $1kg$ is equal to $2.21lb$, What does this statement mean? What should be the proper way of making comparison?

Answer 1

We know that every unit of the same terms are interchangeable to each other. Similarly here we can convert the kg into lb. Mass is known to us. We know the weight formula so we can now convert the kg into lb.

Complete step by step answer:
As per the question we can say that the statement that is given to us $1kg$ is equal to $2.21lb$, states that they are inter convertible so that we can change the kg into lb which is also a unit of weight.
We know weight is the product of mass and acceleration due to gravity.
Mathematically we can write it as,
$W = mg$
On earth surface we can write this equation as,
Mass = $1kg = 1slug$
Gravity = $9.8m{s^{ - 2}} = 32.2ft{s^{ - 2}}$ this is the constant value of the earth.
We can also write,
$W = 1kg \times 9.8m{s^{ - 2}} = 9.8N$
The weight of $1kg$ is $9.8N$.
Where $9.8N$ is equal to $2.21lbs$.
The proper way of making this comparison is the unit convert where one unit is converted to another by using its formula.

Note: $1kg$ weights $2.21lb$ on the surface of the earth. Here the weight and mass both differ to each other as weight varies from place to place as it depends upon the gravity while mass of a body will remain the same in all the places. Keep in mind that slug is a derived unit of mass in a weight based system of measures. This system of measure either derives from its mass and derives from its force unit.