Two balls of masses $m_1$ and $m_2$ are separated from each other by a powder charge placed between them. The whole system is at rest on the ground. Suddenly,the powder charge explodes and the masses are pushed apart. The mass $m_1$ travels a distance $s_1$ and stops. If the coefficients of friction between the balls and the ground are the same,the mass $m_2$ stops after travelling the distance:

• A
  $s_2 = \frac{m_1}{m_2} s_1$
• B
  $s_2 = \frac{m_2}{m_1} s_1$
• C
  $s_2 = \frac{m_1^2}{m_2^2} s_1$
• D
  $s_2 = \frac{m_2^2}{m_1^2} s_1$