# Homework Help: Average velocity of hiker

1. Sep 25, 2011

### physicsgurl12

1. The problem statement, all variables and given/known data

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

2. Relevant equations
not sure how to write what i used

3. 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

2. Sep 25, 2011

### I like Serena

It seems you're not done yet!

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.

3. Sep 25, 2011

### 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

4. Sep 25, 2011

### 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.

5. Sep 25, 2011

### physicsgurl12

okay so how do i do that??

6. Sep 25, 2011

### I like Serena

Going back is "minus" vector wise.

7. Sep 25, 2011

### physicsgurl12

so should i do 6.7-1.1/5.1+1

8. Sep 25, 2011

### I like Serena

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

9. Sep 25, 2011

### physicsgurl12

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

10. Sep 25, 2011

### I like Serena

Yeah, I think so too...