Show that acceleration varies as cube of the distance given

[chwala]

Homework Statement

See attached.

Relevant Equations

Rate of change

In my approach i have distance as $(x)$ and velocity as $(x^{'})$, then,

$(x^{'}) = kx^2$

where $k$ is a constant, then acceleration is given by,

$(x^{''}) = 2k(x) (x^{'})$

$(x^{''}) = 2k(x)(kx^2)$

$(x^{''}) = 2k^2x^3$.

Correct?

 

[anuttarasammyak]

It seems OK.