⚙️ Pulley (Atwood Machine)

📖 The Physics

A pulley (কপিকল) just redirects the string, so both masses share one tension and move together — one up while the other comes down. To find their motion, apply F = ma to each mass separately, then combine the two equations.

That gives the system's acceleration and the string tension. If the two masses are equal, it simply stays balanced.

Make the masses more unequal and the acceleration grows (up to g when one side is tiny). The tension always sits between the two weights — less than the heavy weight (so it accelerates down) and more than the light one (so it accelerates up).