# Help a highschooler with physics homework?

1. Sep 14, 2006

### phantomcow2

We just started vectors today and introduced the I and J axes. He insists we use I and J instead of X and Y, thats okay.

So basically here is the question asked:

A person riding a bike has a velocity v=32m/s I + 12m/s J. Determine the magnitude of hte velocity and hte bikes direction. Determine the total distance traveled by the person on the bike after 120 seconds.

SO my first step I would think is to draw quadrant 1 of an XY plane. Is the direction northeast? I would imagine this is the case because there is no mention of any negative velocities, so quadrant 1 is + in both axes.
TO determine the magnitude of velocities...
Do I simply draw a right triangle, with point (0,0) as the vertex with a 90 degree? Move up 32 in the I, and 12 in hte J?
Then use A^2+B^2=C^2 to find the hypotenuse? The hypotenuse being the magnitude?

I THINK that part I have right. BUt it is the total distance that stumps me, can somebody give some insight?

2. Sep 14, 2006

### chroot

Staff Emeritus
You're correct about how to find the magnitude of the velocity.

Keep in mind that "the magnitude of the velocity" is a fancy way of saying "speed." Once you've found the speed, just multiply it by time to get distance.

- Warren

3. Sep 14, 2006

### phantomcow2

oooh, that threw me off. Speed makes it all come together in my mind :). Well now, I get 34.18m/s as a magnitude of velocity. So x 120 and 4101.6m

Thanks! I will have more questions to come tomorrow I am SURE

4. Sep 14, 2006

### NateTG

Excellent homework post. By the way, there's a forum dedicated to those somewhere around here...