An object travels North at #6 m/s# for #4 s# and then travels South at #3 m/s# for #5 s#. What are the object's average speed and velocity?

1 Answer
Apr 13, 2017

Answer:

#"Speed" = (4.3333333333bar3m)/s#

#"Velocity" = (1m)/s#

Explanation:

Calculating the average speed is very easy but I'm first doing average velocity because it requires more attention

#color(white)(xxxxxxxxxxxx)O#
#N larr larr larr larr A rarr rarr rarr rarr S#

Where A is the point where the object started from
N is north and S is south and is considered the midway between north andsouth. In our real earth that's equator
O is the object

The main trick here is to measure the distance between A and the point where the car stops.

Distance covered towards North

#(6m)/s xx 4 = 24m#

It is 24meters ahead of A towards north direction

It can be represented like this
#color (white)(xxxxxxxx )24m#
#color(white)(xxxxx )Ocolor(white)(xx )harr #
#N larr larr larr larr A rarr rarr rarr rarr S#

Distance between A and O = 24m

Now calculate the distance moved towards South

#(3m)/s xx 5 = 15m#

#color(white)(xxxxx )Orarr"by 15 meters" #
#N larr larr larr larr A rarr rarr rarr rarr S#

Distance moved from A

= 24m -15m = 9m

Time elapsed

4s + 5s = 9s

= 9m/9s = 1m/s is the velocity

#"Speed" = "distance"/"time"#

Distance is the distance covered can be anywhere in any direction in any zigzag pattern means the object can move back and front , eft and right.

So distance covered = 24m + 15m = 39m

Time elapsed

4s + 5s = 9s

= #"distance"/"time" = (39m)/(9s) = (4.3333333333bar3m)/s#