An object travels North at 4 ms1 for 3 s and then travels South at 6 ms1 for 8 s. What are the object's average speed and velocity?

1 Answer
Apr 28, 2016

The average speed is the total distance over the time, the average velocity is the total displacement over time. Speed = 5.45 ms1, velocity = 3.27 ms1.

Explanation:

Find the distances traveled in each step:

d=vt=43=12m# N

d=vt=68=48m# S

The total distance is the simple sum of these two distances, 60 m.

The total displacement is the difference between them, 36 m S

The total time is 8+3=11 s

To find the average speed:

speed=distancetime=60115.45 ms1

To find the average velocity:

velocity=distancetime=36113.27 ms1