need a bit of help with j-hat and i-hat in a collision

by jperez94
Tags: collision, ihat, jhat
jperez94 is offline
Feb29-04, 12:36 PM
P: 4
Hey there, I'm lost with this one:

Two 3-kg masses have velocities v(1)= 2m/s i-hat plus 3m/s j-hat and v(2)= 4m/s i-hat minus 6m/s j-hat. Find the velocity of the center of mass of the system.

Now, I know how to go about calculating the velocity of the center of mass (v(cm)= m(1)V(1)+m(2)V(2)/m(1)+m(2)

The thing that throws me off is the j-hats and i-hats. How do I come out with a vector number? I thought of the pothagarem(sp?) therom, but decided that couldnt work. Any ideas? Thanks.
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himanshu121 is offline
Feb29-04, 12:57 PM
himanshu121's Avatar
P: 661
u mean pythagoras Theorem , it should work
HallsofIvy is offline
Mar1-04, 11:03 AM
Sci Advisor
PF Gold
P: 38,886
Treat "i-hat" and "j-hat" as two separate problems. Then put them back together into the "momentum vector" with i and j components.

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