G forces

Calculate car deceleration (as a multiple of gravitational acceleration g = 9.81 m/s²) when a vehicle in a frontal collision slows down uniformly from a speed 61 km/h to 0 km/h in a 1.1 meters trajectory.

Final Answer:

G =  13.3 g

Step-by-step explanation:

$$\begin{gathered} g=9.81{\text{m/s}}^2 \\ v=61\text{km/h}\to \text{m/s}=61:3.6\text{m/s}=16.94444\text{m/s} \\ s=1.1\text{m} \\ s=\frac{1}{2}a{t}^2 \\ 2s=a{t}^2 \\ a=\frac{\Delta v}{\Delta t} \\ v=at=\frac{2s}{t} \\ t=\frac{2\cdot s}{v}=\frac{2\cdot 1.1}{16.9444}=\frac{198}{1525}\doteq 0.1298\text{s} \\ a=v/t=16.9444/0.1298\doteq 130.5065{\text{m/s}}^2 \\ G=a/g=130.5065/9.81=13.3\text{g} \end{gathered}$$

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