Physics - Center of Mass Question with Solution | TestHub

$\sin \varphi =\frac{4}{5}$, so along the line of centres (x):$u_{2m}=5\cos \varphi =3,u_m=-10\cos \varphi =-6$. x-momentum is zero; restitution:$v_{2m,x}^{\prime }-v_{m,x}^{\prime }=e\left(u_{m,x}-u_{2m,x}\right)=\frac{5}{9}(-9)=-5$. With$v_{m,x}^{\prime }=-2v_{2m,x}^{\prime }:3v_{2m,x}^{\prime }=-5\Rightarrow v_{2m,x}^{\prime }=-\frac{5}{3}$. Tangential component of 2m is unchanged:$5\sin \varphi =4$. So${\vec{v}}_{2m}^{\prime }=-\frac{5}{3}\hat{i}+4\hat{j}$. Answer: (B)