Find Average Velocity of X & Y Components

[Heat]

Homework Statement

A http://www.maniacworld.com/squirrel-obstacle-course.html has x- and y-coordinates ( 1.2 m, 3.9 m) at time t1=0 and coordinates ( 5.5 m, -0.60 m) at time t2 = 3.1 s.

For this time interval, find the x & y component of the average velocity.
Express your answer using two significant figures.

The Attempt at a Solution

This is what I did
First I drew how I would imagine it would look like.

Then I decided xf-xi / tf-ti = vax

-.60 - 1.2 /3.1 = -1.8/3.1 = -.580

 

[learningphysics]

Homework Statement

A http://www.maniacworld.com/squirrel-obstacle-course.html has x- and y-coordinates ( 1.2 m, 3.9 m) at time t1=0 and coordinates ( 5.5 m, -0.60 m) at time t2 = 3.1 s.

For this time interval, find the x & y component of the average velocity.
Express your answer using two significant figures.

The Attempt at a Solution

This is what I did
First I drew how I would imagine it would look like.

Then I decided xf-xi / tf-ti = vax

-.60 - 1.2 /3.1 = -1.8/3.1 = -.580

but -0.60 is y2, not x2...

 

[Heat]

ok

my mistake (obviously) :P

5.5 - 1.2 /3.1 = 4.3/3.1 = 1.38

 

[learningphysics]

Yeah, that looks right. Do the same for vy. The question asks for 2 significant figures though...

 

[Heat]

Ok I did the other questions regarding this crazy squirrel,

but this question got me

Find the direction of the average velocity. below the x axis.

I graphed it.

x com = 1.4
y com = -1.5

arc tan of (-1.5/1.4) = -.82

why is this wrong.?

 

[learningphysics]

Is that in radians? Does the question ask for degrees or radians?

Although the first parts asked for the answer in 2 significant figures... you should keep more decimal places for the next calculations...

ie: use arctan( -1.4516/1.387)

 

[Heat]

since it still says use two sigs

I did what you mentioned above and I got

-.8081519332

so I rounded to

-.81

still wrong.

and yes in degrees

 

[learningphysics]

since it still says use two sigs

I did what you mentioned above and I got

-.8081519332

so I rounded to

-.81

still wrong.

and yes in degrees

But -0.81 is in the answer in radians... do you have the calculator set up for degrees? What is the anwer in degrees?

 

[Heat]

haha, I guess that is what I get for using my graphing calc, I forgot the last time I used it I set it up for radians. Thank you for your explation. :)