Consider a two body-body system where m1$m_1$ and m2$m_2$ are attached to each other by a string when m1 is pulled with an additional string then it pulls m2 along with it. The acceleration is constant since the system demonstrates a single body behavior. Then if m2 is lesser than m1 it means that the force transmitted to m2 has been reduced because if it was the same then it would produce a greater acceleration and vice versa. What causes this change in force? Why isn't the original force transmitted to m2