It's about one-tenth as heavy as a Grand Piano
In other words, 50 kilograms is 0.110 times the weight of a Grand Piano, and the weight of a Grand Piano is 9.10 times that amount.(for Steinway & Sons, Model D Concert Grand Piano)
A Grand Piano, of the kind used for concert performances in large music halls, weighs 450 kg. Well-made pianos such as this may last 75 to 100 years.
It's about ten times as heavy as a Gallon of Paint
It's about ten times as heavy as a Cat
In other words, the weight of a Cat is 0.10 times 50 kilograms.(Felis catus) (Domestic; healthy weight)
The average domestic cat should weigh between 4 and 5 kg. Cats are known for their righting reflex, which allows them to land on their feet and survive falls from heights of 1 m (3 ft) up to about 21 m.
It's about one-tenth as heavy as a Polar Bear
In other words, 50 kilograms is 0.0969 times the weight of a Polar Bear, and the weight of a Polar Bear is 10.30 times that amount.(Ursus maritimus) (adult, male)
An adult, male polar bear weighs between 352 and 680 kg. Polar bears are so heavily insulated by their 9.9 cm (3.9 in) layer of blubber that they are often difficult to detect using infrared photography sensors.
It's about one-tenth as heavy as a Grizzly Bear
In other words, the weight of a Grizzly Bear is 10.40 times 50 kilograms.(a.k.a. brown bear, a.k.a. silver bear, Ursus arctos horribilis) (Adult, male, coastal area population average)
An adult, male grizzly bear from a coastal area (where food is plentiful) can weigh up to 521 kg. In spite of their tremendous size, grizzly bears can run at speeds of up to 55 kph (34 mph).
It's about one-fifteenth as heavy as a Cow
In other words, the weight of a Cow is 14 times 50 kilograms.(for Holstein, a.k.a. Holstein Friesian, a.k.a. Friesian, Bos primigenius) (adult, heifer)
A mature Holstein cow (the well-known black-and-white, spotted breed of cow) typically weighs 680 kg. President William Howard Taft (1909 - 1913) kept a Holstein cow named Pauline Wayne on the White House grounds — a gift from a Wisconsin senator and the source of the First Family's milk.
It's about seventeen times as heavy as a Brick
In other words, the weight of a Brick is 0.059 times 50 kilograms.(Standard, traditional face brick - 1,900 cu. cm (120 cu. in))
A standard, traditional face brick weighs an average of 2.9 kg. The steeple of the Church of St. Martin in Landshut, Germany is said to be the tallest brick tower in the world at a height of 130.6 m (428.5 ft) and was constructed using an estimated 650,000 bricks.