View source for Weight

Claimed by mxu86 (Michael Xu)

A page about weight as a property of matter.

==The Main Idea==

'''In physics, weight describes the [[Gravitational Force]] upon a mass, usually relative to Earth or a planet.''' Depending on the source, weight may be defined as a scalar - the magnitude of the gravitational force on an object - or a vector equal to gravitational force. 
An object's weight is commonly confused with mass, but instead it is a force that depends on another body of matter, while mass is an intrinsic property of matter. 

===A Mathematical Model===

A mass ''m'''s weight near the surface of the Earth is represented by <math>{\vec{W} = \vec{F}_{g} = {m}\vec{g}}</math> where ''g'' is the gravitation acceleration of Earth, <math>{{<0,-9.8,0>} \frac{m}{{s}^{2}}}</math>.

Scalar weight would simply be the magnitude of the gravitational force, <math>{\left\vert{\vec{W}}\right\vert = \left\vert{\vec{F}_{g}}\right\vert}</math>, and it can be simplified to <math>{\left\vert{\vec{W}}\right\vert = mg}</math>.

===A Computational Model===

A simple segment of code that calculates the both scalar and vector weight (gravitational force) exerted upon a ball. 

[[File:Weightcode.JPG|400px|thumb|right]]

<code>
     '''# Initializing sphere object'''
     
     ball=sphere(pos=vec(0,0,0), radius=0.02, color=color.yellow, make_trail=true)

     '''# Defining constants'''
     g = vec(0,-9.8,0) ''#gravitational acceleration''
     ball.m=0.1        ''#mass of the ball in kg''
     W = ball.m*g      ''#weight of the ball on Earth''

     '''# Printing values
     print("Scalar weight of the ball:", mag(W), "kg m/s^2 or N")
     print("Force of gravity exerted on the ball:", W, "kg m/s^2 or N")

</code>

==Examples==

Be sure to show all steps in your solution and include diagrams whenever possible

===Simple===
''Determine the weight in Newtons of a 55 kilogram barbell on the surface of Mars, given the gravitational acceleration'' <math>{g}_{Mars} = 3.75\frac{m}{{s}^{2}}</math>''.''


::<math> \left\vert{\vec{W}}\right\vert = m{g}_{Mars} </math>
::<math> \left\vert{\vec{W}}\right\vert = 55kg*3.75\frac{m}{{s}^{2}} </math>
::<math> \left\vert{\vec{W}}\right\vert = 206.25 N </math>

===Middling===
===Difficult===

==Connectedness==
#How is this topic connected to something that you are interested in?
#How is it connected to your major?
#Is there an interesting industrial application?

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.

== See also ==

[[Vectors]]

[[Mass]]

[[Gravitational Force]]

[[Gravitational Potential Energy]]

===Further reading===

Chabay & Sherwood: Matters and Interactions -- Modern Mechanics Volume 1, 4th Edition

===External links===

[http://www.physicsclassroom.com/ Physics Classroom lessons and notes]

==References==

1. "Weight." Wikipedia. Wikimedia Foundation. Web. 1 Dec. 2015. <https://en.wikipedia.org/wiki/Weight#Gravitational_definition>.

2. "Types of Forces." Types of Forces. Physics Classroom. Web. 1 Dec. 2015. <http://www.physicsclassroom.com/class/newtlaws/Lesson-2/Types-of-Forces>.

3. "The Value of G." The Value of G. Physics Classroom. Web. 1 Dec. 2015. <http://www.physicsclassroom.com/class/circles/Lesson-3/The-Value-of-g>.


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