Difference between revisions of "Kinetic Energy"
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| − | '''Kinetic energy''' represents the [[energy]] | + | '''Kinetic energy''' represents the [[energy]] associated with the [[motion]] of an object.<ref>Serway and Beichner, ''Physics for Scientists and Engineers'', Fifth Edition</ref> It is defined as: |
| − | K ≡ [[mass|m]][[velocity|v]]<sup>2</sup> / 2 for a point mass and <math> K = {1 \over 2}mV^2 + {1 \over 2} I \omega ^2 </math> for a body, where I is the body's moment of inertia and omega is the body's angular velocity. | + | K ≡ [[mass|m]][[velocity|v]]<sup>2</sup> / 2 for a point mass and <math> K = {1 \over 2}mV^2 + {1 \over 2} I \omega ^2 </math> for a rigid body, where I is the body's moment of inertia and omega is the body's angular velocity. |
| − | The change of kinetic energy | + | The change of kinetic energy is equal to the total [[work]] done on it by the resultant of all [[force|forces]] acting on it. For a point mass this can be expressed as: |
Σ''W'' = ΔK = mv<sub>f</sub><sup>2</sup> / 2 - mv<sub>i</sub><sup>2</sup> / 2 | Σ''W'' = ΔK = mv<sub>f</sub><sup>2</sup> / 2 - mv<sub>i</sub><sup>2</sup> / 2 | ||
Revision as of 12:44, November 8, 2007
Kinetic energy represents the energy associated with the motion of an object.[1] It is defined as:
K ≡ mv2 / 2 for a point mass and <math> K = {1 \over 2}mV^2 + {1 \over 2} I \omega ^2 </math> for a rigid body, where I is the body's moment of inertia and omega is the body's angular velocity.
The change of kinetic energy is equal to the total work done on it by the resultant of all forces acting on it. For a point mass this can be expressed as:
ΣW = ΔK = mvf2 / 2 - mvi2 / 2
Where vi is speed at t = 0 and vf is speed at time = t.
Kinetic energy is a scalar and has the same units as work (i.e. Joule).
References
- ↑ Serway and Beichner, Physics for Scientists and Engineers, Fifth Edition