Calculate Acceleration of Two Blocks Hanging From a Pulley | Atwood's Machine

Apply Newton's Laws to a popular physics problem consisting of two blocks hanging from a string which is run up over a pulley. If one block is heavier than the other then the heavier block will pull harder on the string causing that block to accelerate downward and the other block to accelerate upward.

The net force or total force on each block is not zero, which is why each block accelerates. So by applying Newton's Second Law to each block individually, then combining those equations in a system of equations, it is possible to generate an equation for the total acceleration of the entire system.

This problem is a central problem in introductory physics and engineering. It commonly comes up in high school physics including AP Physics 1, AP Physics C Mechanics. It also appears in various forms on the A Level and JEE exams.