Answer
$W_2$ = $3W_1$
Work Step by Step
The distance from $20$ $cm$ to $30$ $cm$ is $0.1$ $m$ so with $f(x)$ = $kx$ we get
$W_1$ = $\int_0^{0.1}{kx}dx$ = $k\left[\frac{1}{2}x^{2}\right]_0^{0.1}$ = $\frac{1}{200}k$
$W_2$ = $\int_{0.1}^{0.2}{kx}dx$ = $k\left[\frac{1}{2}x^{2}\right]_{0.1}^{0.2}$ = $k\left(\frac{4}{200}-\frac{1}{200}\right)$ = $\frac{3}{200}k$
Thus
$W_2$ = $3W_1$
