A student walks east 100 meters in 2 minutes. She then walks north 200 meters in 4. Which statement is true?
Her velocity changes because her speed varies.
Her velocity changes because her direction changes.
Her velocity is constant because her direction is constant.
her velocity is constant because her speed is constant.
The statement "Her velocity changes because her direction changes" is true.
Velocity is a vector quantity that includes both speed (magnitude) and direction. In this scenario, the student first walks east (changing her direction) and then north (changing her direction again). Since the direction changes, her velocity also changes.
Note: Speed is a scalar quantity that only represents the magnitude of an object's velocity. In this case, the speed may be constant (if the distance is proportional to the time), but the velocity is changing due to the changes in direction.