Final answer:
The person hit by a bullet that sticks to the bulletproof vest would hardly move due to the significant mass difference between the bullet and the person. Momentum is conserved, but often the vest absorbs most of the kinetic energy and momentum, further reducing any motion of the person.
Step-by-step explanation:
When a bullet strikes a person wearing a bulletproof vest and sticks to the vest, the person would only move slightly, if at all. To calculate the speed at which the person moves, conservation of momentum is used. However, the mass of the bullet is usually much smaller than the mass of the person. Therefore, even if the bullet transfers all its momentum to the person and the vest, the speed of the person post-impact would be very small given the large mass difference. Assuming no other external forces and using the equation p = mv (momentum equals mass times velocity), the velocity v of the person after impact could be computed if the mass m of the bullet and its velocity were known. Nevertheless, the question lacks sufficient details to provide a specific numerical answer. In practice, the vest absorbs much of the bullet's kinetic energy and momentum, minimizing the motion of the person further.