Video Transcript
Velocities can be represented as
arrows. Which of the following represents
two velocities that are unequal? Is it option (A), (B), or (C)?
Recall that velocity is a vector
quantity. And we often represent vectors
using arrows, like we have here. We know that a vector is defined by
its direction and also by its length, which symbolizes its magnitude.
If we measure the vector lengths
with a ruler, we can see that each pair of vectors have the same length in all three
cases, meaning they’re equal in magnitude. So it’s only the direction of the
vectors in each pair that can make them different.
Looking at (A), we can see two
vectors placed one after the other. And they’re both pointing in the
same direction, so the two are equal.
Looking at (B), the vectors are
more spaced out, but they’re parallel and still have the same direction as each
other. So they’re equal as well.
In fact, the only difference
between vectors is found in option (C), where we can see that the vectors are
pointing in opposite directions. Since these two velocity vectors
point in different directions, we know that they’re unequal. And therefore, the correct answer
is (C).
