At mean position, the velocity of the particle in S.H.M. is maximum, so kinetic energy is KE=21kA2, where, k is spring constant.
We also know that, kinetic energy is related to momentum as KE=2mp2.
Now, from both equations, we have
21kA2=2mp2 (Here, momentum is conserved)
⇒(A2A1)2=m1m2=9001024
⇒A2A1=3032=1516=16−116
∴α=16