An object travels North at 8 m/s for 6 s and then travels South at 7 m/s for 4 s. What are the object's average speed and velocity?
2 Answers
Average speed
Average velocity
Explanation:
Explanation:
The distance North,
s_n = v_n*t_n = 8 m/s*6 s = 48 m
The distance Sorth,
s_s = v_s*t_s = 7 m/s*4 s = 28 m
Average speed
"Average speed " = "total distance"/"total time" " " So, plugging in our data,
"Average speed " = (48 m + 28 m)/(6 s + 4 s) = (76 m)/(10 s)
"Average speed" = 7.6 m/s
Average velocity
"Average velocity " = "total displacement"/"total time"
To determine displacement, we need a rule for what the positive direction is. I declare that North is the positive direction. So, plugging in our data,
"Average velocity" = (48 m - 28 m)/(6 s + 4 s) = (20 m)/(10 s)
"Average velocity" = 2.0 m/s
I hope this helps,
Steve