Newton's law of gravitational attraction states that when two particles of masses m1 and m2 are separated by distance r, they attract each other with equal and opposite forces. The attraction force acts along the line joining the particles and varies directly as the product of their masses and inversely as the square of the distance between them, where G is the universal constant known as the gravitational constant. The gravitational attraction force exerted by the Earth on an object is the object's weight. It is the product of the object's mass and acceleration due to gravity, expressed in newton. Gravity separators, drop hammers, and gravity conveyors are a few mechanical tools that work on the principle of Newton's law of gravitation. Consider the drop hammer forging process. Here, the hammer of a specific weight is raised to a certain height and then allowed to fall freely. Since the Earth has a strong gravitational pull, the hammer always falls. The force created by this fall gives the required shape to the workpieces.