The difference between speed and velocity
3 marks · NormalA car travels at a constant speed of 20 m/s north and then turns to travel 20 m/s east. Explain how its speed and velocity change.
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Speed stays the same, but velocity changes because direction changes.
Also accept: Speed is unchanged; velocity is different.; The car's speed remains 20 m/s, but velocity changes direction.
Common mistakes: Only discussing speed
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Marking points
B1 · 1 mark · States speed stays the same (20 m/s)
B2 · 1 mark · States velocity changes/direction changes
B3 · 1 mark · Mentions that velocity depends on both magnitude and direction (vector)
Worked solution
The speed (20 m/s) does not change, but velocity depends on both speed and direction. Since the direction changes from north to east, the velocity is different, even though the magnitude is the same.