24
sarah, who has a mass of 55 kg, is riding in a car at 20 m/s. she sees a cat crossing the street and slams on the brakes! her seatbelt stops her from flying forward, bringing her to rest in 0.5 seconds. how much force did the seatbelt put on sarah?

F = (mass)(acceleration) = ma

m = 55 kg

Vi = 20 m/s

t = 0.5 s

Vf = 0 m/s (since she was put to rest)

a=(Vf-Vi)/t

a=(0-20)/5

a = 40 m/s^2 (decelerating)

F = ma = (55 kg)(40 m/s^2)

F = 2200 N

Hope this answer will be a good help for you.

There is no reason to think the results are biased or not conducted properly but you should not assume the results are correct just because they were done in a laboratory so the answer would be c. it is likely to be reliable because the results support the conclusion presented.