To calculate the maximum impact force on a helmet, one must consider the weight of the head model, the height of the drop, and the impact duration. Standard testing methods for helmets exist, and it's suggested to refer to these rather than starting from scratch. The design of the helmet significantly influences the maximum force it can withstand, as different materials and shapes affect impact absorption. Elastic impacts generate higher peak forces compared to plastic impacts due to the nature of energy transfer during collisions. Understanding these principles is crucial for designing effective helmets that minimize injury.