Calculating Work Done by a Force on a Particle Moving Along the X-Axis

[torn616]

Homework Statement

A particle moves only along the x-axis, and is subject to a force towards the origin of magnitude kx^3. if the particle moves from x1 to x2 how much work does this force do on it? (consider the case x1<x2)

Homework Equations

W=Fd

The Attempt at a Solution

kx^3(x2-x1)

 

[torn616]

I just noticed that the force would change as the particle moved along the x-axis. Taking the anti-derivative of kx^3 from x1 to x2 I got (kx2^4)/4 - (kx1^4)/4 = k/4 (x2^4-x1^4)

 

[Jilang]

Looking good to me!