The difference between speed and velocity
2 marks · EasyA car’s velocity changes from +15 m/s to -5 m/s in 10 seconds. What does the negative sign mean in this context? State your answer clearly.
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The car is now moving in the opposite direction.
Also accept: The negative means the direction is opposite to the original.; It means the car has reversed direction.
Common mistakes: Only saying 'it is slowing down'; Ignoring the direction change
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Marking points
B1 · 1 mark · States that negative sign shows a change in direction.
B2 · 1 mark · Explains that the car is moving in the opposite direction to before.
Worked solution
The negative sign in velocity means the car is travelling in the opposite direction to its original movement.