An MRI machine with a magnet strength of 1-2 Tesla can exert a force of approximately 3N/cm³ on small objects like nails made of iron or steel. The force experienced by the nail is influenced by its volume, but when considering acceleration, it can reach around 45g, where g represents gravitational acceleration. The discussion emphasizes the necessity of having an inhomogeneous magnetic field for accurate force generation. A typical length scale of 1 meter is assumed for these calculations. Overall, the estimates provide insight into the significant forces MRI machines can exert on small metallic objects.
