Velocity
Average Velocity
Average velocity is represented by v. To determine the average velocity, the net displacement is divided by the time such that
\[
\text{average velocity} = \frac{\text{displacement}}{\text{time}} \quad \text{or} \quad \bar{v} = \frac{\overrightarrow{d}}{t},
\]
where the bar (–) above v signifies “average.”
Example:
An airplane takes off at 10:00 a.m. and flies a straight path at 350 km/h until 1:00 p.m. Its velocity then changes to 400 km/h in the same direction until it lands at 3:30 p.m. What is its average velocity for the entire flight?
Given
v1 = 350 km/h
v2 = 400 km/h
t1 = 3 h
t2 = 2.5 h
Solution
To determine the average velocity of the airplane, determine the net distance it has covered and the total time elapsed. During the first three hours of its flight, its distance was
- d1= v1 t1
- = (350 km/h)(3 h)
- = 1050 km,
and during the next two hours and a half,
- d2 = v2 t2
- = (400 km/h)(2.5 h)
- = 1000 km.
