What does a negative velocity mean?
To understand this question, it is important to know that velocity has both a direction and a magnitude. The magnitude can be expressed by the unit m/s, however the direction is expressed by a vector. To distinguish between two directions in velocity, you can have a positive and a negative vector: vectors that point in the opposite direction. Therefore, a negative velocity means that the direction of that velocity is opposite to the other velocity (with the positive value).
TD
Related Physics A Level answers
All answers ▸Why does a small puddle of water evaporate at room temperature, even though the temperature is way below the boiling point of water?
How can a car be changing velocity yet not changing speed?
A cricketer throws a ball vertically upwards so that the ball leaves his hands at a speed of 25 m/s. Calculate the maximum height reached by the ball, the time taken to reach max. height, and the speed of the ball when it is at 50% max. height.
In an electric propulsion system, alpha particles are accelerated through a potential difference of 100kV at an average rate of 10^20 alpha particles per second. Calculate the average thrust the system can provide.