What Was the Average Velocity of the Hiker During the Trip?

[physicsgurl12]

Homework Statement

a hiker walks 6.7 miles to the east in 5.1 hours. then turns around and walks 1.1 miles to the west in 1 hour. what was her average velocity during the trip?
A 1.2mph
B 1.3mph
C .92mph
D 3.9mph

Homework Equations

not sure how to write what i used

The Attempt at a Solution

6.7/5.1=1.3
1.1/1=1.1
1.3+1.1=2.4/2=1.2

 

[I like Serena]

It seems you're not done yet!

Let's start with the word "velocity".
Do you know what it means?
That is, is it a scalar or a vector?

Second, the term "average velocity".
What you should know is that you shouldn't average the speeds of the first part and the second part.
Instead you should calculate the total distance and divide that by the total time.

 

[physicsgurl12]

velocity is a vector because it has a magnitude and a direction.
so i should do something like 6.7+1.1/5.1+1=7.8/6.1=1.27

 

[I like Serena]

You just got the "average speed".
To get the "average velocity" you need to take into account that the second part of the trip is back.

(And please add parentheses when they are required. )

 

[physicsgurl12]

okay so how do i do that??

 

[I like Serena]

Going back is "minus" vector wise.

 

[physicsgurl12]

so should i do 6.7-1.1/5.1+1

 

[I like Serena]

Shall we make that: (6.7-1.1)/(5.1+1)?
The parentheses are really required.
Otherwise you're quite right.

 

[physicsgurl12]

okay. i got why the () are required. haha thanks i think I am almost done

 

[I like Serena]

Yeah, I think so too...