Wednesday, January 18, 2012

Forces - Pushing and Pulling – Weight v. Mass

A force pushes or pulls a mass.  But, what exactly is a mass anyway?


Weight v. Mass

A force pushes or pulls a mass.  But, what exactly is a mass anyway?

Weigh yourself.  The scale tells you that you weigh 190 pounds (lbs).  After wondering how you got so heavy, a brilliant idea dawns on you.  You can lose weight by moving to Denver …  or if you’re already in Denver, try Bolivia, or … the Moon.


Mass is a constant measure of matter within an object.  Your mass remains constant wherever you go.


Weight is a measure of the force created on a mass by gravity.  This is why you lose weight by going to the Moon.



Force

Force is an attribute of physical action or movement measured by the ability of the attribute to move an object.

Force = Mass x Acceleration

F = ma


In the case of weight, this formula can be written as

Weight = Mass x Acceleration due to Gravity

W = mg



Be aware that our discussions from here on will apply use "mass" rather than "weight."