My Solution
after the string is cut we have a system well defined by the following free body diagram:
I argue that the acceleration of the block A in the x direction (##a_A^x##) is:
$$ F_A = T_1 $$
$$ ma_A^x = T_1 $$
$$ a_A^x = \frac{T_1}{m} $$
I argue that the acceleration of the block B in...