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Immy2000

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~~~~~~~~~~~~~~~~~~~~~~~~~~~~Solved~~~~~~~~~~~~~

A student travels at a constant velocity of 8.0 m/s north for 25 minutes, and then 5.0 m/s south for 15 minutes. Calculate the students...

a) Average Velocity

b) Average Speed

a) http://library.thinkquest.org/C0110840/Images/vel.gif

b) Vav =

a) Vav =

t1= 0s

t2= 15 minutes = 900s

d1= 0m

d2= (5 m/s * 900s)

Vav =

900 s

=

? I do not even understand velocity, so I just plugged in what I thought seemed logical as initial start I assumed was 0 and if you travel from 0 to x1 and then from x1 to x2, it would therefore be x2 being the final..thing and 0 being the initial..thing.

b) Vav =

Vav =

2400 s

Vav = 6.875 =

? WOW I don't even know

I just can't seem to understand velocity which probably is the cause of my inability to differentiate what to do for either speed or velocity in general..

## Homework Statement

A student travels at a constant velocity of 8.0 m/s north for 25 minutes, and then 5.0 m/s south for 15 minutes. Calculate the students...

*(Answer in brackets)*a) Average Velocity

*(Answer 3.1 m/s North)*b) Average Speed

*(Answer 6.9 m/s)*## Homework Equations

a) http://library.thinkquest.org/C0110840/Images/vel.gif

b) Vav =

*[Delta]*d/*[Delta]*t## The Attempt at a Solution

a) Vav =

*[Delta]*d/*[Delta]*t*[Delta]*d = d2-d1*[Delta]*t = t2-t1t1= 0s

t2= 15 minutes = 900s

d1= 0m

d2= (5 m/s * 900s)

*[Delta]*d= 4500m - 0m = 4500m*[Delta]*t= 900s - 0sVav =

__4500 m__900 s

=

**5.0 m/s [North]**? I do not even understand velocity, so I just plugged in what I thought seemed logical as initial start I assumed was 0 and if you travel from 0 to x1 and then from x1 to x2, it would therefore be x2 being the final..thing and 0 being the initial..thing.

b) Vav =

*[delta]*d\*[Delta]*t*[Delta]*t = [t2 + t1]*[Delta]*d = [d2*t2] + [d1*t2]*[Delta]*d = (8 m/s * 1500 s) + (5 m/s * 900 s) = 16500 m*[Delta]*t = (900 s + 1500 s)Vav =

__16500 m__2400 s

Vav = 6.875 =

**6.9 m/s**? WOW I don't even know

*why*it worked because I always though it was d2-d1 not d1+d2. I am so confused! Please, all help would be much appreciated. :)I just can't seem to understand velocity which probably is the cause of my inability to differentiate what to do for either speed or velocity in general..

## Homework Statement

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