Bridging connection between Newton's second law and Work

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Homework Help Overview

The discussion revolves around connecting Newton's second law, F = ma, to the expression m/2(dv²/dx). Participants are exploring the mathematical relationships and steps involved in this transition.

Discussion Character

  • Mathematical reasoning, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to manipulate the equation F = ma and questions how to proceed after deriving mv(dv/dx). Some participants suggest differentiating v² and integrating both sides of the equation to explore the relationship further.

Discussion Status

Participants are actively engaging with the problem, offering suggestions for differentiation and integration. There appears to be a productive exploration of the mathematical steps, although no consensus has been reached on the final interpretation or outcome.

Contextual Notes

There is an indication of a disconnect in the steps presented in the course book, and participants are questioning the assumptions and definitions involved in the problem setup.

negation
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Homework Statement



I'm trying to bridge F =ma to m/2(dv2/dx). It was shown in the course book I have but there's a huge disconnection in the steps.

The Attempt at a Solution

F =ma = m.(dv/dt) = m(dv/dx . dx/dt) = mv(dv/dx). Where do I take it from here?
 
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Formally differentiate d/dx(v^2). What do you get?
 
negation said:

Homework Statement



I'm trying to bridge F =ma to m/2(dv2/dx). It was shown in the course book I have but there's a huge disconnection in the steps.

The Attempt at a Solution




F =ma = m.(dv/dt) = m(dv/dx . dx/dt) = mv(dv/dx). Where do I take it from here?

Multiply both sides of your equation by dx to get

F dx = mv dv

Integrate both side, what do you get?
 
dauto said:
Multiply both sides of your equation by dx to get

F dx = mv dv

Integrate both side, what do you get?

Both sides?
I could arrive at the conclusion if I were to integrate only the left argument.

∫F(x).dx = ∫ma.dx = ∫m(dv/dt).dx = ∫m(dv/dx . dx/dt) .dx = ∫m(dv/dx . v).dx = ∫m*dv.v = ∫mv.dv = m∫dv . ∫v.dv = m (0.5v2) = 0.5mv2 + C
 
rude man said:
Formally differentiate d/dx(v^2). What do you get?

derivative of v2 = 2v(dv/dx)
 
Last edited:

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