Step 1: Relation between energy and amplitude.
For a simple harmonic oscillator,
\[
E\propto A^2
\]
Thus,
\[
\frac{E_2}{E_1}=\left(\frac{A_2}{A_1}\right)^2
\]
Step 2: Calculate the new amplitude.
Amplitude decreases by
\[
1.5\%
\]
Hence,
\[
A_2=98.5\% \text{ of } A_1
\]
\[
A_2=0.985A_1
\]
Step 3: Find the ratio of energies.
Using
\[
E\propto A^2,
\]
\[
\frac{E_2}{E_1}=(0.985)^2
\]
\[
\frac{E_2}{E_1}=0.970225
\]
Therefore, the fraction of energy lost is
\[
1-0.970225
\]
\[
=0.029775
\]
\[
\approx 0.03
\]
Hence, percentage loss in energy is
\[
0.03\times 100=3\%
\]
Step 4: Final conclusion.
Therefore, the mechanical energy lost in each cycle is
\[
\boxed{3\%}
\]