Understanding Energy and Kinetic Equations: A Quick Question Answered

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K in the equation K=1/2mv^2 represents the kinetic energy of an object with mass m and velocity v, not the change in kinetic energy. To determine the change in kinetic energy, one must calculate the difference between final and initial kinetic energy, expressed as Kfinal - Kinitial, which equals the total work done (Wtotal). The discussion also touches on potential energy, emphasizing that only changes in energy can be calculated, and absolute kinetic energy requires an arbitrary reference point for a body at rest. The conversation highlights the importance of defining a reference value for kinetic energy when considering a stationary object. Understanding these concepts is crucial for accurately analyzing energy transformations in physics.
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When they say K=1/2mv^2 does K mean the change of kinetic energy? because Wtotal= the change of kinetic energy...
 
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linnus said:
When they say K=1/2mv^2 does K mean the change of kinetic energy? because Wtotal= the change of kinetic energy...

1/2 mv^2 gives the kinetic energy of an object with mass m moving with velocity v. To find the change in kinetic energy, one would have to solve for Kfinal - Kinitial, which would be equal to the Wtotal of which you speak.
 
to calculate change in K.E we have formula 0.5*mass*(v*v-u*u)...
think about potential energy
we can calculate only change (d)
and arbitarily assume U at some point and express potential energy as
d+U(initial)=U(final).
actualy we can perform only relative analysis
and therefore diff of K.E of a moving body velocity v with respect to body at rest can be obtained by substituting u=0..

but to calculate absolute K.E we must take an arbitarily some value of K.E for body at rest...and then add it to the difference

and so what do you think is most appropriate, logical & convinient value to be given to the body at rest .??


well your question was good but a bit vague inexpression I think..:smile:
 
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