# A mass M, attached to a horizontal spring, executes S.H.M. with amplitude $A_1$. When the mass M passes through its mean position then a smaller mass m is placed over it and both of them move together with amplitude $A_2$. The ratio of $(\frac{A_1}{A_2})$ is :
( A ) $(\frac{M}{M+m})^{^{1/2}}$
( B ) $(\frac{M+m}{M})^{^{1/2}}$
( C ) $\frac{M+m}{M}$
( D ) $\frac{M}{M+m}$