# 12.1 Pulley Problems - Part I, Set up the Equations

In the figure, pulley A is fixed to the ceiling. An ideal rope is attached at one end to block 1 of mass $$m_1$$, it passes around a second pulley, labelled B, and its other end is fixed to the ceiling. A second ideal rope attaches pulley B to a second block of mass $$m_2$$. As a result, pulley B and block 2 move together.

The goal of the problem is to calculate the accelerations of blocks 1 and 2.

The solution of this problem is divided into four parts:

• Part I : Set up the system of equations.
• Part II: Constraint condition - find the relationship between the accelerations.
• Part III: Constraint condition using a virtual displacement argument.
• Part IV: Solving the system of equations.