Answer:
B. 45 km/hr south
Explanation:
Velocity is a vector quantity which consists of:
- A magnitude, given by the ratio between displacement and time taken for the motion
- A direction, which corresponds to the direction of the displacement
Let's analyze now each option:
A. 12 m/s --> this is not a velocity: this is a speed, because it does not specify the direction, so it is only a scalar quantity
45 km/hr south --> this is a velocity, because it specificies both magnitude (45 km/h) and direction (south)
C. 55 km/hr --> again ,this is not a velocity, but it is a speed, because it does not specify the direction, so it is only a scalar quantity
D. -5 m/s2 east --> this is not a velocity, but it is an acceleration, since the units of measurement are the ones of acceleration (m/s^2, while for the velocity should be m/s or km/h)
