a scale.
You would use pounds or kilograms to measure the weight of a person.
pounds
You would use the unit of measurement called "kilograms" or "pounds" to measure the weight of a car.
The tool that a person would use to measure out a pound is called a scale. A scale can be used to weigh people as well. Pounds are a form of measure used on the Imperial system.
You would use the metric unit "kilograms" to measure the weight of a bag of groceries.
Ounces
a calculator
Newtons.
if i were you , i would use kg
pounds
Kilogram is a measure of weight - so you would use it to weight something. You would probably use it for objects that are large enough to make using grams unnecessary.