B2-CT01
(a) Even though the path lengths are the same for the two riders (23 km) the displacement is
greater for Rider A because the diagonal distance is greater. Displacement is a vector
quantity, and the length (magnitude) of the displacement is the straight line distance
from the start point to the end point.
(b) Since the displacement is greater for Rider A, because the diagonal distance is greater,
Rider A’s average velocity, which is displacement divided by elapsed time, has a greater
magnitude also.
B2-SCT02
None of them are entirely correct. Bob is correct that the displacements of Riders A and B are
opposite to each other, because the diagonal distance is the same with the starting and ending
points reversed. But the displacements of Riders A and C are the same because they have the
same start and end points.
B2-RT03
All are zero.
Since the starting and ending points for all trips are the high school the displacements for all
these roundtrips are zero regardless of the total distance traveled.
B2-SCT04
Bunmi is correct.
The students are actually comparing the average speed to the magnitude of the average velocity.
The distance traveled will be larger than the magnitude of the displacement, so the average
speed being the distance divided by the elapsed time will be larger than the magnitude of the
average velocity which is the magnitude of the displacement divided by the time.