Introduction to the ModelDescription and AssumptionsThis model is applicable to a point particle (or to a system of objects treated as a point particle located at the system's center of mass) when the external forces are known or needed. It is a subclass of the model Momentum and External Force defined by the constraint dm/dt = 0. Learning ObjectivesStudents will be assumed to understand this model who can:
S.I.M. Structure of the ModelCompatible SystemsA single point particle, or a system of constant mass that is treated as a point particle located at the system's center of mass. Relevant InteractionsExternal forces must be understood sufficiently to draw a free body diagram for the system. Internal forces will always cancel from the equations of Newton's 2nd Law for the system and can be neglected. Law of ChangeMathematical RepresentationUnknown macro: {latex}
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[ \sum \vec Unknown macro: {F}
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] \end
As with all vector equations, this Law of Interaction should really be understood as three simultaneous equations: Unknown macro: {latex} \begin Unknown macro: {large} [ \sum F^ Unknown macro: {rm ext}
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= ma_ ] _ Unknown macro: {y}
= ma_ ] Unknown macro: {rm ext}
_ Unknown macro: {z}
= ma_ ]\end Diagrammatical RepresentationsRelevant ExamplesExamplesInvolvingVectorComponents"> Examples Involving Vector ComponentsExamplesInvolvingNormalForce"> Examples Involving Normal ForceExamplesInvolvingApparentWeight"> Examples Involving Apparent WeightExamplesInvolvingTension"> Examples Involving TensionExamplesInvolvingInclinedPlanes"> Examples Involving Inclined PlanesExamplesInvolvingStaticFriction"> Examples Involving Static FrictionExamplesInvolvingKineticFriction"> Examples Involving Kinetic FrictionExamplesInvolvingCentripetalAcceleration"> Examples Involving Centripetal AccelerationAllExamplesUsingthisModel"> All Examples Using this Model
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Photos courtesy: US Army by Spc. Michelle Waters |
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