It's about 350 times as heavy as a Battery (D)
In other words, the weight of a Battery (D) is 0.0027 times 50 kilograms.(Alkaline)
A "D" size battery weighs 0.1350 kilograms. The D size battery is the oldest of the modern battery sizes, first invented by the National Carbon Company in 1898.
It's about 550 times as heavy as a Deck of Cards
In other words, the weight of a Deck of Cards is 0.0019 times 50 kilograms.(ISO 216 B8 size, a.k.a. "poker size" 63 x 88 mm, 52-card deck)
A deck of 52 ISO 216 B8-size playing cards weighs 0.094 kilograms. Utilizing nearly 3,700 decks, the record-holding largest card tower was built in early 2010, stood over 3.5 m (11 ft), and weighed over 272 kg.
It's about 750 times as heavy as a Battery (C)
In other words, the weight of a Battery (C) is 0.0013 times 50 kilograms.(Alkaline)
A "C" size battery weighs 0.065 kilograms. C batteries are typically used in medium-drain devices such as musical instruments.
It's about 850 times as heavy as a Tennis Ball
In other words, 50 kilograms is 867 times the weight of a Tennis Ball, and the weight of a Tennis Ball is 0.00115 times that amount.(ITF Standard; for Type 2 ball)
Per International Tennis Federation standard, regulation tennis balls must weigh about 0.0577 kilograms. Competition balls are also tested for bounce height, with the standards requiring that a ball dropped from 254 cm must bounce back to a height of 135 cm to 147 cm.
It's about 1,000 times as heavy as a Golf Ball
In other words, 50 kilograms is 1,089 times the weight of a Golf Ball, and the weight of a Golf Ball is 0.0009183 times that amount.(per R&A USGA Rules of Golf; maximum rule weight)
According to the Rules of Golf (as approved by the United States Golf Association and the Rules Committee of the Royal and Ancient Golf Club of Saint Andrews), golf balls must weigh no more than 0.04593 kilograms. Golf balls are not required to have the familiar dimpled pattern, but the design has been popular since its invention in 1905 because it reduces drag while increasing lift.
It's about 1,500 times as heavy as a Light Bulb
In other words, the weight of a Light Bulb is 0.00067 times 50 kilograms.(a.k.a. lamp) (for A19-size, 60w, incandescent bulb by Bulbrite; package weight)
A standard, sixty-watt light bulb weighs about 0.034 kilograms. The tightly-coiled filament inside a bulb of this size would measure about 579mm if uncoiled and stretched out.
It's about 2,000 times as heavy as a Battery (AA)
In other words, 50 kilograms is 2,100 times the weight of a Battery (AA), and the weight of a Battery (AA) is 0.00048 times that amount.(Alkaline)
An "AA" size battery weighs 0.024 kilograms. AA batteries came into common use during World War II and were given their name by the American National Standards Institute (ANSI) Committee C18 because they were smaller than the "A" size batteries which were invented first.