$\frac{v}{4}$
Step 1: The velocity of the center of mass is given by: \[ V_{{cm}} = \frac{m_1 v_1 + m_2 v_2}{m_1 + m_2} \] where $m_1 = M$, $v_1 = v$, $m_2 = 2M$, and $v_2 = 0$.
Step 2: Substituting the values: \[ V_{{cm}} = \frac{M v + 2M \times 0}{M + 2M} \] \[ V_{{cm}} = \frac{M v}{3M} = \frac{v}{3} \]
Step 3: Therefore, the correct answer is (D).
Kepler's second law (law of areas) of planetary motion leads to law of conservation of
Kepler's second law (law of areas) of planetary motion leads to law of conservation of