Question

A German shepherd weighs $56.8\;lb$. How much does it weigh in kg?

Answer 1

We know that weight can be measured in many units and two such units are pounds(lb) and kilograms(kg). Kilograms is the SI unit of measurement. And pound is a non-SI unit and is also frequently used to measure or weigh items in the US. And both are interconvertible.
Formula used:
$1\;lb=0.4536\;kg$

Complete answer:
We know that weight is defined as the force exerted on the given object due to gravity. Clearly weight is a vector quantity since it is nothing but the gravitational force acting on the body. And is expressed as $W=mg$ where $W$ is the weight of the object due to mass $m$ under the gravity $g$. Since weight is also a force, it also has the units newton N.
However in everyday use, we use kg to weigh or measure weight. This roughly means we are weighing the mass of the given object. And the US measures the weight in terms of lb. As both are a measure of weight, they can be easily converted as follows,
$1kg=2.205lb$, or 1 kg equals 2.205 pounds.
Similarly, pounds in terms of kilograms we have, $1\;lb=0.4536\;kg$ or 1 pound is equal to 0.4536 kilograms.
Here, given that the dog weighs, $56.8 \;lb$
Then, in terms of kg, we have, $56.8\times 0.4536 =25.76 \;kg$
Thus the required answer is $25.76\;kg$

Note:
Weight and mass are similar yet two different quantities. And hence don’t confuse with each other. The mass is a property of the given object and remains the same irrespective of the location or gravity. Whereas weight is the gravitational force experienced by a given object. And clearly weight depends on gravity and hence varies with gravity.