Decelleration

In a braking test, a vehicle that travels at 51 km/h stops in 5 s. What is the acceleration?

Correct answer:

a =  -2.8333 m/s²

Step-by-step explanation:

$$\begin{gathered} v_1=51\text{ km/h}\to \text{ m/s}=51\mathrm{/}3.6\text{ m/s}=14.16667\text{ m/s } \\ {v}_2=0\text{ m/s } \\ t=5\text{ s } \\ a={\displaystyle \frac{\mathrm{\Delta }v}{\mathrm{\Delta }t}} \\ a={\displaystyle \frac{v_2-v_1}{t}}={\displaystyle \frac{0-14.1667}{5}}=-{\displaystyle \frac{17}{6}}=-2.8333{\text{m/s}}^2 \end{gathered}$$

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