nus mass by initial velocity over time). Now this equation can be rearranged so that it reads ft=mv-mu (force multiplied by time equals mass by final velocity minus mass by initial velocity). mv-mu is the 'change in momentum', but momentum will always stay the same. Knowing this, if the time (t) interval is lengthened, then the force (f) of the impact is lessened (Impulse). A seatbelt does exactly that, it prolongs the time interval impact reducing the force. If the force is too great, then there is the possibility of the seatbelt cutting through the skin, which is wh!
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