Force given velocity as function of space.

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Homework Help Overview

The problem involves determining the force acting on a particle of mass m, given that its speed varies with position as v(x) = ax^-n, with the condition that v(x=0) = 0 at t=0. The context is rooted in classical mechanics, specifically relating to force, mass, and acceleration.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relevance of differentiating velocity with respect to time versus space, questioning how to derive acceleration from a velocity function defined in terms of position. There is also uncertainty regarding the interpretation of the variable "a" in the equation.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem and the relationships between force, mass, and acceleration. Some guidance has been offered regarding the use of the chain rule for differentiation, but no consensus has been reached on the approach to take.

Contextual Notes

There is a noted confusion regarding the relationship between velocity as a function of space and its implications for acceleration, as well as the role of the variable "a" in the equation.

deblimp
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Homework Statement


The speed of a particle of mass m varies with space as v(x) =ax^-n
v(x=0)=0 at t=0.
Find F(x).

Homework Equations


F=ma=m dv/dt

The Attempt at a Solution


I am not really sure where to start from. Would x(t) or f(t) be relevant?
 
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You have Newton's law defining the relationship between the force and the acceleration. You also have the velocity as a function of time. Now you need the acceleration. And you can plug that in for the force.
 
No we do not have velocity as a function of time, we have it as a function of space. Therefore we can't just differentiate and get the accel.
 
Usually, these problems make use of the chain rule of differentiation.
 
Is "a" acceleration or just a constant in the equation?
 
deblimp said:

Homework Statement


The speed of a particle of mass m varies with space as v(x) =ax^-n
v(x=0)=0 at t=0.
Find F(x).

Homework Equations


F=ma=m dv/dt

The Attempt at a Solution


I am not really sure where to start from. Would x(t) or f(t) be relevant?

Try rearranging dv/dt
 

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