A. What is the mass of a pencil or pen?

The mass will depend on the amount of material that comprises the pencil or the pen. Mass is an intrinsic property that you can calculate by taking a measurement of the weight using the formula: w = mg. Where (g) is the acceleration on the mass due to gravity (provided it is "close" to the Earth's surface).

A couple of examples:

If a pen weighs 1 lb (a seriously heavy pen), then its mass would be

m = 1 lb/32 (ft/s^{2}) = 0.03125 slugs (slug is the unit of mass in the British system)

Likewise if a pen weighs 1 N, then its mass would be

m = 1N/9.81 (m/s^{2}) = 0.1019 kilograms

## Comments

It should be noted however, that people often misuse mass and weight interchangeably even though they are two discrete quantities. If you put a pen on a scale in the lab (due to the design of the scales used) you will get a readout that indicates a mass quantity in grams, but if you step on your own bathroom scale you will see your weight in pounds.