Engineers compare two seat belt designs, X and Y, in crash tests. In each test, a crash-test dummy of mass 60 kg travelling at 12 m/s is brought to rest by the seat belt. The stopping times are shown in the table.
| Seat belt design | Stopping time |
|---|---|
| X | 0.080 s |
| Y | 0.20 s |
Calculate the magnitude of the average resultant force on the dummy for each seat belt design.
Explain which seat belt design would give a passenger the lower risk of injury.