 A system can consist of one or more objects that affect each other.  Often, these objects are connected or in contact.

 Draw Free Body Diagram for each object  Resolve forces at angles into x & y components  Direction of acceleration is the positive direction (may be a different direction for each object)  Write F net equations for x & y directions for each object  Solve  Connected objects have the same acceleration  Ropes have the same tension on each side * * unless the pulley has mass (AP Physics)

aa Many times you will solve using methods for 2 equations with 2 unknowns