Acceleration

Example 2.3 Comparing Distance Traveled with Displacement: A Subway Train

What are the distances traveled for the motions shown in parts (a) and (b) of the subway train in Figure 2.18?

Strategy

To answer this question, think about the definitions of distance and distance traveled, and how they are related to displacement. Distance between two positions is defined to be the magnitude of displacement, which was found in Example 2.2. Distance traveled is the total length of the path traveled between the two positions. In the case of the subway train shown in Figure 2.18, the distance traveled is the same as the distance between the initial and final positions of the train.

Solution

The displacement for part (a) was +2.00 km. Therefore, the distance between the initial and final positions was 2.00 km, and the distance traveled was 2.00 km.
The displacement for part (b) was $−1.5 \, km$ . Therefore, the distance between the initial and final positions was 1.50 km, and the distance traveled was 1.50 km.

Discussion

Distance is a scalar. It has magnitude but no sign to indicate direction.

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()