Question

calculate the average acceleration from a period of 2 s to 10 s.
(a) average acceleration = -0.125 m/s²
(b) average acceleration = -1.375 m/s²
(c) average acceleration = -0.500 m/s²
(d) average acceleration = 0.917 m/s²

Explanation:

Step1: Recall average - acceleration formula

The formula for average acceleration is $a_{avg}=\frac{\Delta v}{\Delta t}$, where $\Delta v = v_f - v_i$ and $\Delta t=t_f - t_i$.

Step2: Determine initial and final velocities and times

From the graph, at $t_i = 2\ s$, $v_i=5\ m/s$. At $t_f = 10\ s$, $v_f=- 6\ m/s$. And $\Delta t=t_f - t_i=10 - 2=8\ s$.

Step3: Calculate $\Delta v$

$\Delta v=v_f - v_i=-6 - 5=-11\ m/s$.

Step4: Calculate average acceleration

$a_{avg}=\frac{\Delta v}{\Delta t}=\frac{-11}{8}=-1.375\ m/s^2$.

Answer:

B. average acceleration = -1.375 m/s²