Position and velocity vectors of a squirrel

AI Thread Summary
The discussion revolves around calculating the average velocity of a squirrel based on its position at two different times. The average velocity components were correctly calculated as 1.4 m/s in the x-direction and -1.3 m/s in the y-direction. However, there was confusion regarding the magnitude of the average velocity, which the book states is 1.9 m/s, while the user initially calculated it as 0.52 m/s. The misunderstanding arose from not squaring the negative value correctly, as squaring any number results in a positive value. Clarification was provided that the magnitude should indeed be calculated using the squared values of both components.
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Homework Statement


A squirrel has x and y coordinates (1.1m, 3.4m) at time t1=0.0s and coordinates (5.3m, -0.5m) at time t2=3.0s. For this time interval, find (a) the components of the average velocity, and (b) the magnitude and direction of the average velocity.

Homework Equations


vavg=\Deltax/\Deltat.

The Attempt at a Solution


Xv avg = (5.3m - 1.1m)/(3.0s - 0.0s) = 1.4 m/s
Yv avg = (-0.5m - 3.5m)/(3.0s - 0.0s) = -1.3 m/s

I know these values are correct because I checked them in the back of the book. I don't understand how they get the magnitude and direction of the average velocity.

http://img704.imageshack.us/img704/8484/20240551.png

Here's a picture of the average velocity vectors. The resultant vector (the diagonal line) should be \sqrt{(-1.3 m/s)^2+(1.4m/s)^2}, which is 0.52 m/s. The book says it's 1.9 m/s, which means they made Yv avg a positive 1.3 m/s. Why did they do this?
 
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Wow I'm an idiot. It would help if I did (-1.3)^2 instead of -1.3^2 like I just typed in Latex.
 
cdotter said:
I know these values are correct because I checked them in the back of the book. I don't understand how they get the magnitude and direction of the average velocity.
It's just the change in distance over the change in time(simply the time between when you start measuring the change in distance and when you stop measuring the change in distance). It's the distance between (x1, y1) and (x2, y2)
Here's a picture of the average velocity vectors. The resultant vector (the diagonal line) should be \sqrt{(-1.3 m/s)^2+(1.4m/s)^2}, which is 0.52 m/s. The book says it's 1.9 m/s, which means they made Yv avg a positive 1.3 m/s. Why did they do this?
Because (-1.3)2 = (-1.3)*(-1.3) = 1.69; Any number2 is positive.
 
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