Changing limits on an integral

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The discussion centers on the derivation of relativistic kinetic energy, specifically transitioning from the integral expression KE = ∫0s (d(mv)/dt) ds to KE = ∫0mv v d(mv). The key insight provided by Dan is the definition of velocity, v ≡ ds/dt, which allows for the adjustment of integration limits when changing the variable of integration to d(mv). This clarification is essential for understanding the relationship between the variables in the context of relativistic motion.

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dimensionless
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I have a textbook with the equation below. The equation is a derivation for relativistic kinetic energy.
[tex]KE = \int_{0}^{s} \frac{d(mv)}{dt}ds = \int_{0}^{mv} v d(mv)[/tex]

I should really know this, but I don't. How do I get from the second expression to the third?
 
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dimensionless said:
I have a textbook with the equation below. The equation is a derivation for relativistic kinetic energy.
[tex]KE = \int_{0}^{s} \frac{d(mv)}{dt}ds = \int_{0}^{mv} v d(mv)[/tex]

I should really know this, but I don't. How do I get from the second expression to the third?

[tex]v \equiv \frac{ds}{dt}[/tex] is the definition of v. Since the integral is now an integral of d(mv) then the limits will go in terms of the new integration variable. (I am assuming we are speaking of an object that starts from rest and accelerates somehow to a speed v.)

-Dan
 
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