Time, Velocity, and Speed

Check Your Understanding

A commuter train travels from Baltimore to Washington, DC, and back in 1 hour and 45 minutes. The distance between the two stations is approximately 40 miles. What is (a) the average velocity of the train, and (b) the average speed of the train in m/s?

Solution

(a) The average velocity of the train is zero because $x_{\mathrm{f}}=x_{0}$ ; the train ends up at the same place it starts.

(b) The average speed of the train is calculated below. Note that the train travels 40 miles one way and 40 miles back, for a total distance of 80 miles.

$\begin{gathered} \frac{\text { distance }}{\text { time }}=\frac{80 \text { miles }}{105 \text { minutes }} \\ \\ \frac{80 \text { miles }}{105 \text { minutes }} \times \frac{5280 \text { feet }}{1 \text { mile }} \times \frac{1 \text { meter }}{3.28 \text { feet }} \times \frac{1 \text { minute }}{60 \text { seconds }}=20 \mathrm{~m} / \mathrm{s} \end{gathered}$

Callback before_footer in local_aigrade component should be migrated to new hook callback for core\hook\output\before_footer_html_generation

line 7225 of /lib/moodlelib.php: call to debugging()
line 7292 of /lib/moodlelib.php: call to {closure}()
line 71 of /lib/classes/hook/output/before_footer_html_generation.php: call to get_plugins_with_function()
line 987 of /lib/classes/output/core_renderer.php: call to core\hook\output\before_footer_html_generation->process_legacy_callbacks()
line 97 of /mod/book/tool/print/index.php: call to core\output\core_renderer->footer()