In general, a significant amount of force is needed to dislocate a shoulder. The shoulder is a ball-and-socket joint, which means the head of the upper arm bone (the humerus) fits into a rounded cavity in the shoulder blade (the glenoid fossa). The joint is held in place by ligaments, tendons, and muscles that form the shoulder capsule.
For the shoulder to dislocate, these stabilizing structures must be overcome, and the head of the humerus must be forced out of the glenoid fossa. This typically requires a strong impact, such as from a fall, a sports injury, or a direct hit to the shoulder.
Without specific measurements or detailed knowledge of the circumstances, it is difficult to provide an exact figure for the amount of force needed to dislocate a shoulder. However, it is safe to say that it would be a substantial force, beyond the average amount of pressure or impact encountered during everyday activities.