Questions: The following problem is similar to a problem from your textbook. The table below shows the position s of a car at time t. Round your answers to one decimal place.
t(sec) 0 0.2 0.4 0.6 0.8 1
s(ft) 0 2.7 2.8 5.2 5.8 7.6
Estimate the velocity at t=0.2 by averaging the average rate of change over the left and right intervals.
Transcript text: The following problem is similar to a problem from your textbook. The table below shows the position $s$ of a car at time $t$. Round your answers to one decimal place.
\begin{tabular}{|c|c|c|c|c|c|c|}
\hline $\mathrm{t}(\mathrm{sec})$ & 0 & 0.2 & 0.4 & 0.6 & 0.8 & 1 \\
\hline $\mathrm{s}(\mathrm{ft})$ & 0 & 2.7 & 2.8 & 5.2 & 5.8 & 7.6 \\
\hline
\end{tabular}
Estimate the velocity at $t=0.2$ by averaging the average rate of change over the left and right intervals.
Solution
Solution Steps
Step 1: Calculate the Average Velocity
Given the positions at times $t_a=0$ and $t_b=0.8$ are $s_a=0$ and $s_b=5.8$, respectively,
the average velocity over the interval $[0, 0.8]$ is calculated using the formula:
\[ \text{Average Velocity} = \frac{s_b - s_a}{t_b - t_a} = \frac{5.8 - 0}{0.8 - 0} = 7.2 \text{ ft/s} \]
Step 2: Estimate the Instantaneous Velocity at a Specific Time
To estimate the velocity at time $t_c=0.2$, we find two time points $t_{c1}=0$ and $t_{c2}=0.4$ such that $t_{c1} < t_c < t_{c2}$.
The positions at these times are $s_{c1}=0$ and $s_{c2}=2.8$, respectively.
The estimated velocity at $t_c$ is calculated as:
\[ \text{Estimated Velocity at } t_c = \frac{s_{c2} - s_{c1}}{t_{c2} - t_{c1}} = \frac{2.8 - 0}{0.4 - 0} = 7 \text{ ft/s} \]
Final Answer:
The average velocity over the interval $[0, 0.8]$ is 7.2 ft/s,
and the estimated instantaneous velocity at time $t_c=0.2$ is 7 ft/s.