A Simple Pendulum: Concentrating Weight on a String or Rod

[jrm2002]

Mass and weight!

It is said:

"A simple pendulum, is a concentration of mass on the end of a string or rod"

Instead of using the word mass why don't we use the word "weight"?

 

[neutrino]

Weight, as per one defenition of the word, refers to gravitational force exerted on a mass.