A $20-$cm$-$long rod with a diameter of $0\mathrm{.}29$ cm is loaded with a $5000$ N weight. Determine the true strain at this load when the diameter decreases to $0\mathrm{.}25$ cm $.$ Assume that the necking point has not been reached. $($Round the final answer to four decimal places.$)$

The true strain on the rod when its thickness changes from $0\mathrm{.}29$ cm to $0\mathrm{.}25$ cm on being loaded with a weight of $5000$ N is